* FTSE 100 up 0.6 pct
* FTSE 250 up 1.1 pct
* Sterling rally aids mid-cap index
* Frankie & Benny's owner surges on sales rise
* Just Group slips for 2nd straight day
* Interserve slumps with administration imminent (Recasts, adds company news items, updates with closing prices)
By Muvija M and Shashwat Awasthi
March 15 (Reuters) - Britain's mid-cap index hit a 5-month high on Friday, tracking a rally in sterling as talks between the Northern Irish Democratic Unionist Party and British ministers over Prime Minister Theresa May's Brexit deal were described as "good".
The domestically-focused FTSE 250 .FTMC hit its highest since Oct. 10 and ended the day up 1.1 percent, while the blue-chip FTSE 100 .FTSE rose 0.6 percent for its fifth straight session in the black.
Industrials, consumer and financial stocks together added more than 140 points to the mid-cap index.
The Northern Irish party that props up May's government said it had held good talks with ministers on additional assurances that would be needed for them to back her twice-defeated Brexit deal. were also lifted by gains in Frankie & Benny's owner Restaurant Group RTN.L , which jumped 10 percent after annual pretax profit exceeded its forecast and recently acquired noodle bar chain Wagamama posted strong sales. main index .ISEQ , often considered a gauge of Brexit mood, added 1.2 percent.
Britain's parliament on Thursday approved asking the European Union for a short delay if lawmakers can agree on a Brexit deal by March 20, or a longer delay if nothing can be agreed in time. Spreadex analyst Connor Campbell said the need for the EU to unanimously approve any delay meant some uncertainty remained, drawing some investors to defensive stocks.
British American Tobacco BATS.L added 2.7 percent and Prudential PRU.L rose 2.6 percent.
Credit rating agency Moody's also warned uncertainty around the Brexit outcome was very high and would continue to weigh on investment, hiring and spending decisions, which was credit negative for UK issuers.
Housebuilders .FTNMX3720 , considered to be among most vulnerable to economic hits stemming from Brexit, rose on the back of Thursday's vote and after a trading update from mid-cap Berkeley.
Berkeley BKGH.L rose 1.9 percent after it stuck to its profit target despite softness in Britain's housing market caused by Brexit uncertainties.
Retirement services specialist Just Group JUSTJ.L slipped for a second session to close 4.2 percent lower, adding to a 12 percent fall on Thursday which followed a cash call. IRV.L shares lost more than a third of their value and were suspended from trading as the heavily indebted outsourcer was set to go into administration after shareholders rejected a rescue plan. financial heavyweights gained on Sino-U.S. trade optimism.