Tony Blair is to give a public assurance that he will quit as Britain’s prime minister by the summer of next year in a last-ditch attempt to quell a growing revolt by Labour MPs keen to force him out even sooner.

After a day of high drama at Westminster on Wednesday – which saw seven members of the government resign after calling for Mr Blair to quit immediately – the prime minister agreed with Gordon Brown, UK finance minister, that he would make the statement during the next few days.