Prime Minister Theresa May’s Brexit plans have been thrown into further turmoil as the speaker of parliament rules that she cannot put her divorce deal to a new vote unless it is re-submitted in fundamentally different form.

In a surprise ruling, he said he would not allow a third “meaningful vote” in the coming days on “substantially the same” motion as MPs rejected last week.

With 11 days to go before the UK is due to leave the EU, ministers have warned of a looming “constitutional crisis”.