Washington, D.C. 20549

                                    Form 6-K

                            Report of Foreign Issuer

                      Pursuant to Rule 13a-16 or 15d-16 of
                       the Securities Exchange Act of 1934

                      for the period ended 12 January 2005

                                    BP p.l.c.
                 (Translation of registrant's name into English)

                    (Address of principal executive offices)

     Indicate  by check mark  whether the  registrant  files or will file annual
     reports under cover Form 20-F or Form 40-F.

              Form 20-F        |X|          Form 40-F
                         ---------------               ----------------

     Indicate by check mark whether the registrant by furnishing the information
     contained in this Form is also thereby  furnishing  the  information to the
     Commission  pursuant to Rule 12g3-2(b) under the Securities Exchange Act of

                    Yes                            No        |X|
                         ---------------               ----------------

press release

BP Press Release

January 12, 2005

                      BP Fourth Quarter 2004 Trading Update

This trading update is aimed at providing  certain  estimates  regarding revenue
and trading  conditions  experienced by BP in the fourth quarter ending December
31, 2004, and estimates of certain identified non-operating items expected to be
included  in  that  quarter's   result.   The  fourth  quarter  margin,   price,
realisation,  cost,  production  and other data  referred to below are currently
provisional,  some being drawn from figures  applicable to the first month or so
of the  quarter.  All such data are  subject  to  change  and may  differ  quite
considerably  from the final  numbers that will be reported on February 8, 2005.
The  statement is produced in order to provide  greater  disclosure to investors
and potential investors of currently expected outcomes,  and to ensure that they
all receive equal access to the same information at the same time.

Resources Business : Exploration and Production

Marker Prices
                                         4Q'03     2Q'04     3Q'04     4Q'04
Brent Dated ($/bbl)                      29.43     35.32     41.54     43.85
WTI ($/bbl)                              31.15     38.28     43.88     48.29
ANS USWC ($/bbl)                         29.43     36.99     41.82     42.62
US gas Henry Hub first of month index
($/mmbtu)                                 4.58      6.00      5.75      7.07
UK gas price - National Balance Point
(p/therm)                                27.30     20.70     23.63     28.48

Overview : Exploration and Production

Overall BP production in 4Q'04 is expected to be around 4,090  thousand  barrels
of oil  equivalent  per day  (mboed),  up by some 4 per cent from 3,936 mboed in
4Q'03, and over 4 per cent higher than 3Q'04 production of 3,906 mboed.  Average
production for 2004 as a whole is expected to be around 3,995 mboed, an increase
of more than 10 per cent compared to 2003.

Excluding Russia:

Production in 4Q'04, excluding volumes from our Russian operations,  is expected
to be approximately  3,125 mboed, over 5 per cent higher than the 3Q'04 level of
2,961 mboed due to the  continuing  ramp-up of production in New Profit  Centres
(60 mboed) and the end of the turnaround season in Alaska and the North Sea (120
mboed).  During the quarter we achieved first production from the Holstein field
in the Deepwater  Gulf of Mexico.  The  operational  impacts on production  from
Hurricane  Ivan in the Gulf of Mexico  and the  blow-out  in Temsah in Egypt are
expected to be around 80 mboed during the fourth quarter.

Relative to 3Q'04, liquids realisations did not increase as much as the markers,
reflecting discounts for heavier crudes and the timing of liftings.  Relative to
3Q'04,  gas  realisations in North America did not increase as much as the Henry
Hub marker due to regional pricing differences.

Costs in 4Q'04 are  expected to be around $250m more than in 3Q'04 due to higher
exploration  write-offs,  repairs necessary as a result of Hurricane Ivan in the
US  and  the  Temsah  incident  in  Egypt,  and  planned  increases  in  seismic

The 4Q'04  impact of  Unrealised  Profit in Stock (UPIS) is expected to increase
earnings by approximately $70m.

Russia - BP net share

Production in mboed             4Q'03        2Q'04        3Q'04        4Q'04
TNK-BP: Oil                       669          814          858          882
TNK-BP: Gas                        51           77           87           83
Total                             720          891          945          965
Marker Prices
Urals (NWE - cif) ($/bbl)        27.90        32.32        37.23        37.75
Urals (Med - cif ) ($/bbl)       27.98        32.60        37.41        38.82
Domestic Oil ($/bbl)             16.65        19.71        23.33        22.30

In  4Q'04,  BP's net  share of  production  from  TNK-BP  is  anticipated  to be
approximately 965 mboed, as shown in the table above. 2004 information  includes
TNK-BP's interest in Slavneft.

During  4Q'04,   Urals  NWE  marker  prices  increased  by  $0.52/bbl  with  the
differential to Brent widening to approx $6.10/bbl. Domestic oil prices
decreased slightly relative to 3Q'04 due to seasonal factors.

Increases  in export duty rates  became  effective  on August 1, 2004.  The full
quarter impact of this increase in duties,  along with the effect of lagged duty
reference  prices,  is expected to reduce 4Q operating  profit by  approximately
$170m relative to 3Q'04.

Customer facing Businesses

Refining Indicator Margins ($/bbl)
                                           4Q'03    2Q'04    3Q'04    4Q'04
- West Coast                                6.09    15.41    11.28    10.36
- Gulf Coast                                3.53     9.18     6.99     5.52
- Midwest                                   2.89     9.01     5.01     1.65
North West Europe                           2.21     5.29     4.37     4.72

Singapore                                   2.20     2.80     5.48     8.02

Refining Global Indicator Margin* ($/bbl)   3.14     7.89     6.20     5.60

*The refining Global  Indicator Margin (GIM) is a weighted average based on BP's
portfolio.  Actual  margins may vary  because of refinery  configuration,  crude
slate and operating practices.

The fourth quarter's average global indicator  refining margin is lower than the
previous quarter,  but higher than a year earlier. The refining margins actually
experienced by BP's refineries are expected to be slightly higher than in 3Q'04.
Wider light/heavy spreads, higher clean fuels premia,  locational advantages and
supply  optimization  all increased our realised margins relative to the generic
indicators.  Marketing  margins are  expected to be above those of the  previous
quarter. However the improvement in the Marketing operating environment relative
to 3Q is likely to be more than offset by a $300m charge primarily  related to a
review of carrying values of marketing assets.


Weighted Chemicals Indicator Margin ($/te) *

         4Q'03              2Q'04                 3Q'04                 4Q'04
           109                129                   138                   n/a

*The  Chemicals  Indicator  Margin is a  weighted  average  of  externally-based
product  margins.  It is based on market data collected by Nexant (formerly Chem
Systems) in their  quarterly  market  analyses,  then  weighted on BP's  product
portfolio.  This is  described  more  fully  in the  Group's  quarterly  results

Petrochemicals  sales and margins continue to strengthen as industry utilization
rates rise.  These  benefits  have  partially  been  offset by foreign  exchange
effects in Europe which continue to affect costs.

Gas, Power and Renewables

Gas margins are expected to be substantially higher than 3Q'04. NGL margins have
remained  at  similar  levels to those seen in 3Q'04.  Identified  Non-Operating

Exceptional and non-operating  items in 4Q'04 are expected to amount to a charge
of around $2bn pre-tax. The majority of this charge relates to the
petrochemicals segment, reflecting business exits, the closure of facilities,
and asset impairments.

Interest Expense

The total interest  charge is expected to grow by around one third compared with
3Q'04.  The increase in interest  expense is due to an increase in debt,  higher
interest rates and a reduction in the discount rate applied to provisions  under

Tax Rate

The  effective  tax rate for the  quarter is  expected to be around 35 per cent,
similar  to the  previous  quarter.  The full year rate is  expected  to average
around 35 per cent.


Gearing  for the  quarter  is  expected  to be just  below the bottom end of our
target 25-35 per cent band. Debt has risen due to the impact of the Solvay joint
venture buyout and the normal 4Q phasing of German motor fuel excise taxes.

Share Purchases

During the quarter the company bought back for  cancellation  201 million shares
for a total  consideration  of $2.0bn.  For the year, the total number of shares
bought back for  cancellation  amounted  to 822m at a cost of $7.5bn.  Shares in
issue as at December 31, 2004 were 21,526 million.  As in previous quarters,  BP
has entered  into an  arrangement  that allows it to continue the share buy back
programme during the close period commencing January 1.

Rules of Thumb

As indicated in BP's  strategy  presentation  on March 29, 2004,  the  following
rules of thumb can be used to  estimate  the impact of  changes  in the  trading
environment  on BP's 2004 full  yearpre-tax  results.  These  rules of thumb are
approximate.  In  particular  the  impact  of  large  movements  in the  trading
environment  relative to that of 2003 may differ from those implied by the rules
of thumb.  Particular  differences may arise due to higher  government shares of
Exploration  and  Production  revenues in some  jurisdictions  at current  price
levels, as well as from variations  between the Refining Global Indicator Margin
(GIM)  and  BP's  realized  refining  margins  due to  crude  price  levels  and
differentials,  product price  movements and other  factors.  Many other factors
will  affect BP's  earnings  quarter by quarter.  Actual  results in  individual
quarters may therefore differ  significantly  from the estimates  implied by the
application of these rules.

2004 Operating Environment Rules of Thumb: pre tax per yea

                                                       Full Year
Oil Price - Brent +/- $1/bbl                               $570m
Gas - Henry Hub +/- $ 0.10/mcf                             $110m
Refining - GIM +/- $ 1/bbl                                 $1120m
Petrochemicals - CIM +/- $10/te                            $200m


Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                         BP p.l.c.

Dated: 12 January 2005                           /s/ D. J. PEARL
                                                  D. J. PEARL
                                                  Deputy Company Secretary