Labour MP Lucy Powell has resigned as shadow education secretary, saying that Jeremy Corbyn's position as leader of the party is "untenable".
In a letter to the Labour Party leader, she said: "It is increasingly clear that your position is untenable and that you are unable to command the support of the Shadow Cabinet, the Parliamentary Labour Party and, most importantly, the country.
Given the big challenges faced by our country and our Party over the coming months, and the possibility of an imminent general election, I do not have the confidence that you can bring the Party together, lead us to a General Election and be an effective Opposition.
The leader of the UK's biggest trade union has said the country is 'riven' as a result of the EU referendum.
Len McCluskey told ITV News that the trade unions can help broker a peace deal and reunite the party now the "coup has failed".
Labour leader Jeremy Corbyn said he would 'reach out' to MPs that oppose his leadership but said they should 'respect democracy'.