Image caption The two boats were still tied up at Clogherhead Harbour in County Louth on Thursday

Two Northern Ireland fishing boats have been impounded by the Irish Navy.

They were detained in Dundalk Bay on Tuesday for alleged breaches of fishing regulations.

It follows the collapse of a gentleman's agreement allowing vessels from NI and the Republic reciprocal access to each other's inshore waters.

MPs in Westminster have asked the UK government to explain why the two boats were impounded.

Conservative MP Iain Duncan-Smith said the move had happened "without a huge amount of justification" while Democratic Unionist Party MP Jim Shannon said he was "appalled".

Media playback is unsupported on your device Media caption Jim Shannon 'appalled' over fishing boats seizure

"The fishing boats are very clearly British fishing boats, they were illegally seized in waters that are disputed, waters that belong to this great nation."

A spokesman for the Irish Navy said the two trawlers had been escorted to Clogherhead by a fisheries protection vessel and handed over to police.

'Evidence of hard border'

The Northern Ireland-registered boats, The Amity and The Boy Joseph, were fishing for crabs, lobsters and whelks.

At present, Northern Ireland vessels are banned from fishing inside the Republic of Ireland's six-mile limit.

But the Republic's fleet has not been excluded from Northern Ireland waters.

Fishing industry representatives have been complaining about the situation since the collapse of the so-called Voisinage Agreement in 2016.

They say it is evidence there is already a "hard border" in the Irish Sea.

Image copyright Getty Images Image caption Prawn trawlers from Northern Ireland favour the sheltered waters of Dundalk Bay in the winter

The agreement collapsed after Irish fisherman challenged its legality in Dublin's Supreme Court and it ruled in their favour.

The Irish government promised to legislate to regularise the situation, but it has not yet done so.

It has been claimed this is due to the fact it has now become a potential bargaining chip in wider Brexit fisheries negotiations.

Prawn trawlers from the Northern Ireland fleet favour the sheltered waters of Dundalk Bay in the winter.

The collapse of the agreement has affected about 20 Northern Ireland registered boats that would traditionally have fished there.