UPDATE 2-FTSE 100 snaps four-day winning run amid Brexit worries

* Polymer maker Synthomer tanks after profit alert
* Barclays , WPP gain after Q3 updates
* FTSE 100 down 0.1%, FTSE 250 down 0.2%

(Adds company news items, analyst comments, updates share
moves)
By Muvija M and Shashwat Awasthi
Oct 25 (Reuters) - UK stocks ended Friday on a sour note as
Brexit jitters weighed on sentiment, although the exporter-heavy
FTSE 100 marked its strongest weekly performance in nine months
as the continuing political divide hurt sterling.
The FTSE 100 .FTSE , which had hovered at a near one-month
high in the last two sessions, closed with a 0.1% dip. The FTSE
250 .FTMC lost 0.2%, led lower by a 9.4% fall in Synthomer
SYNTS.L after the polymer maker issued a profit warning.
Brexit updates have been the driving force behind a
roller-coaster ride for the domestic market over the last few
weeks.
While sentiment had improved for battered sectors such as
housebuilders .FTNMX3720 after Prime Minister Boris Johnson
sealed a new Brexit deal, caution returned as lawmakers rejected
his timeline for the deal's passage.
Parliament forced Johnson to ask for another extension to
the departure date, but the European Union has yet to give a
go-ahead to the request. Comments from a source close to French
President Emmanuel Macron that the delay is not justified at
this stage exacerbated worries.
Housebuilders .FTNMX3720 dipped 0.2% on the sector's
fifth straight session in the negative territory.
UK midcaps suffered a bigger hit versus the FTSE 100 on the
back of a continued weakness in the pound due to the political
tug of war over the course of Brexit.
"Markets may not be fully comfortable with diving head first
into riskier assets, until there is greater certainty
surrounding the US-China trade conflict and Brexit," FXTM
analyst Han Tan said.
Helping limit losses on the main index, Barclays BARC.L
advanced 2.4% after reporting a third-quarter profit that topped
analysts' expectations.
WPP WPP.L , the world's biggest ad firm, jumped 6.1% after
it reported a return to quarterly organic sales growth for the
first time in over a year, with a new strategy from boss Mark
Read helping the company win more work. "The turnaround at the advertising giant WPP appears to be
gaining some traction," AJ Bell investment director Russ Mould
said.
Another notable gainer was luxury goods company Burberry
BRBY.L , which added 2.1% as results from Gucci parent Kering
PRTP.PA and Italian jacket maker Moncler MONC.MI allayed
some concerns of a major hit to sales from the Hong Kong
protests. National Grid NG.L weighed with a 2.4% drop after media
outlets reported that New York governor had signalled to cancel
the utility's licence if it fails to cooperate with state
officials regarding a moratorium on natural gas connections.