The restaurant was launched by chef Patrick Powell in 2019, who held his last service there on 14 July.
East London restaurant Allegra is set to close later this month after five years of trading.
The announcement comes less than three weeks after the departure of founder and head chef Patrick Powell, who was formerly head chef at Chiltern Firehouse in London’s Marylebone.
Allegra was launched in 2019 on the seventh floor of the Stratford hotel.
It was praised by Grace Dent in The Guardian for serving the “most sumptuous [soda bread] in London”, as well as offering “elegant yet hearty, jolly and wholly delicious dinners”.
Signature dishes included fried chicken with mustard fruit, pickles and aïoli and pistachio choux with chicken liver and black garlic.
Ashley Shaw, general manager at the Stratford, said: “It has been an absolute pleasure to have witnessed Allegra establish itself on the E20 scene over the past five years and contribute so much to the area’s culinary legacy; however, both Stratford and the wider London landscape have changed inextricably during this time and so it’s important we remain responsive to the market’s needs, hence the requirement for a shift in direction.
“Thank you to everyone we have welcomed to Allegra over the years, and in particular to the brilliant team responsible for all of the fantastic accolades and rave reviews.”
Allegra will hold its final service on 31 August.
The Stratford said it will unveil plans for a new restaurant “in due course”.