UPDATE 2-UK stocks gain on fresh stimulus; energy stocks lift FTSE 100

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* UK finance minister announces 4.6 bln pound stimulus

* Energy stocks track oil prices higher

* Fashion retailer Next gains on better-than-expected sales

* FTSE 100 up 0.6%, FTSE 250 adds 0.9% (Updates to market close, adds analyst comments)

By Shashank Nayar and Shivani Kumaresan

Jan 5 (Reuters) - British shares closed up on Tuesday, as fresh stimulus measures overshadowed risks arising from a new national lockdown imposed to curb the spread of a new coronavirus variant, while energy stocks jumped on higher oil prices.

The benchmark FTSE 100 index .FTSE gained 0.6%, with energy stocks .FTNMX0530 gaining 7%. Oil heavyweights BP BP.L and Royal Dutch Shell RDSa.L were the biggest boosts to the blue-chip index.

Britain began its third COVID-19 lockdown on Tuesday with citizens under orders to stay at home and the government calling for one last major national effort to stem the spread of the virus before mass vaccinations turn the tide. on the market behaviour yesterday and today, I think there is a willingness to look through the economic implications of this current lockdown because it could be the last one," said Connor Campbell, a financial analyst at Spreadex.

Britain on Tuesday announced a new 4.6 billion pound ($6.2 billion) support package, under which retail, hospitality and leisure companies will be able to claim new one-off grants worth up to 9,000 pounds. blue-chip index currently trades at levels seen in early March last year when the coronavirus crisis had just begun to roil markets globally, but has gained nearly 33% from its record 2020 lows as the economy showed signs of improvement led by huge government stimulus packages.

The mid-cap index .FTMC was up 0.9%.

December was the busiest month ever for British supermarkets as tightening COVID-19 curbs and the closure of restaurants, bars and cafés meant shoppers spent 11.7 billion pounds ($15.9 billion) on groceries, industry data showed. MRW.L , Britain's fourth-largest supermarket group, reversed early gains to fall 0.7% even after reporting a rise in underlying sales in its latest trading period encompassing Christmas. fashion retailer Next NXT.L jumped 8% after beating its Christmas sales forecast.