New questions are being raised over the 'backdoor to Britain' following the horrific Belfast knife attack which left a man in his 40s in a critical condition.

Sudanese suspect Hadi Alodid legally crossed from the Republic of Ireland to Northern Ireland three years ago under a long-standing arrangement which means no passport checks are conducted.

Alodid travelled from Sudan to Paris and then onto Dublin, before taking a bus to Belfast and immediately claimed asylum. A few months later the Home Office granted him a five-year visa as a refugee.

The attack on Monday prompted calls for a review of border security measures deployed under the so-called Common Travel Area, or CTA, which encompasses the UK, Northern Ireland and the Republic.

Under the CTA, a key part of the Good Friday Agreement, there are typically no checks on travellers between the Republic and Northern Ireland, nor any on journeys to mainland Britain.

Now it's time to have your say in the Daily Mail's latest poll – do you think passport checks should be brought in at the British-Irish border?

In yesterday's poll, Mail readers were asked: 'Is university a waste of money?' Out of more than 4,000 votes, 81 per cent of you said 'yes' and 19 per cent said 'no'.