Last checked at 
* FTSE 100 down 0.3%, FTSE 250 down 0.2%
* BP weighs on main bourse after Q3 results
* Royal Mail slips after rating cut
(Updates with new headline, no other changes to text)
By Muvija M and Shashwat Awasthi
Oct 29 (Reuters) - London stocks slipped on Tuesday as the
prospect of a December general election put investors in Britain
in a cautious mood, while heavyweight BP slid on lower profits.
Market losses accelerated after a Reuters report that a
"phase one" trade agreement between Washington and Beijing may
not be signed next month, aggravating pessimism over the
U.S.-China trade war.
The FTSE 100 dipped 0.3%, its biggest daily drop in
ten days, pulling back from the previous session's near
one-month high. The mid-cap FTSE 250 was down 0.2%.
Oil major BP was the biggest drag on the main
bourse, sliding 4.2% after reporting a sharp drop in
third-quarter earnings on the back of weaker oil prices and
lower production.
"Stock markets in Europe are largely in the red this
afternoon as the feelgood factor from the Brexit delay has been
replaced by the caution of a possible general election in the
UK," CMC Markets analyst David Madden said.
"Elections can be risky... the Conservatives are polling
well ahead of the Labour Party but traders have learned not to
rely on opinion polls given the events of the past three years,
hence why equities are down."
While the European Union on Monday agreed to a Brexit delay
of up to three months, much remained unclear as lawmakers argued
over how, when or even if the UK should leave the bloc.
British Prime Minister Boris Johnson has said he will again
push for a general election, which the Labour party said it
would now back as a no-deal Brexit was off the table.
Investors are also awaiting the conclusion of this week's
U.S. Federal Reserve meeting, at which the central bank is
expected to cut interest rates for the third time this year to
boost a slowing economy amid an ongoing trade war with China.
"We expect a pickup in global growth in the next six to 12
months, yet see limits to how much monetary easing can be
delivered in the near term," BlackRock analysts said.
"Monetary policy is no cure for the weaker growth and firmer
inflation pressures that may result from sustained trade
tensions."
Financial companies, whose margins would be
under pressure in a low interest rate scenario, were the second
biggest sector-wide drag on the FTSE 100 as they tumbled 1% to
their lowest level in two weeks.
Royal Mail skidded 5% - its steepest one-day drop in
three months - to the bottom of the FTSE 250 after JP Morgan cut
its rating on the stock to 'underweight' from 'neutral'.
Online trading platform Plus500 jumped 5.3% after
reporting a rise in customer additions and revenue for the third
quarter as macro events drove strong trading.
(Reporting by Muvija M, Shashwat Awasthi and Safia Infant in
Bengaluru; editing by Patrick Graham, Andrew Heavens and Jan
Harvey)
