UPDATE 2-UK shares feel Christmas cheer; FTSE on best run in 3 yrs

* FTSE 100 up 0.1%, FTSE 250 up 0.6%
* Blue-chips up for 10th consecutive day
* Midcaps at fresh all-time high
* BT biggest blue-chip loser
* No stock market report Dec 25-26 due to UK holidays

(Adds news item, analyst comment, updates to closing prices)
By Shashwat Awasthi
Dec 24 (Reuters) - Britain's stock market indexes advanced
on Christmas Eve, with the main bourse now on its longest
winning streak in three years and the midcaps touching a fresh
record high, amid a lack of major drivers in thin trading.
The FTSE 100 .FTSE overcame earlier sluggishness to add
0.1% on Tuesday, its 10th straight session of gains. Boosts from
oil major Shell RDSa.L and a 2% rise in domestic bank Lloyds
LLOY.L ensured the index clung to a five-month high.
The mid-cap FTSE 250 .FTMC ended higher for the fourth
straight day as it outperformed its European peers with a 0.6%
gain.
Dealers seemed content to reflect on major developments of
the month, including a breakthrough in U.S.-China trade talks
that partly led to an equities rally earlier this month.
"This holiday period should be rather calm as trade updates
appear very constructive as we near the finalisation of the
phase-one trade deal next month," OANDA analyst Craig Erlam
said.
Prime Minister Boris Johnson's election victory also spurred
on domestic stocks, reflecting hopes of a clear path to Brexit.
Some of that optimism waned after his expressed hard line on
a future trade agreement with the European Union revived fears
of a chaotic Brexit.
Traders are now likely to hold off on making further bets
before gaining further clarity on trade and Brexit in the new
year.
Sterling recovered from a three-week low against the U.S.
dollar, which weighed on exporters such as Unilever ULVR.L and
limited the main index's rise.
Still, the bourse is on course for its best month since
April 2018, while the more domestically-focused midcaps are on
track for a fourth consecutive month of gains and their best
performance since January.
The FTSE 100 looks set for its biggest annual gain since
2016, when Britain voted in a referendum to leave the EU. The
FTSE 250 is on course for its best year in six, as several
long-standing hurdles to Brexit have now been removed.
Telecom firm BT BT.L was the biggest blue-chip loser,
giving up 3%.
Mid-cap gold miner Centamin Plc CEY.L added 2.4%, a day
after it won approval to give its Canadian suitor Endeavour
Mining EDV.TO more time to make a firm takeover offer.