A UNIONIST activist has launched legal action against Boris Johnson claiming his Brexit deal breaches the Good Friday Agreement.

Jamie Bryson, a prominent blogger and loyalist activist who runs the political website Unionist Voice, said Mr Johnson’s deal threatens his right to identify as British.

He also claims it is a threat to peace and stability in Northern Ireland.

Mr Bryson’s lawyers wrote to the Government on Tuesday requesting a judicial review, saying Boris Johnson's new Brexit deal conflicts with the requirements of the 1998 peace treaty because it does not grant the Northern Ireland Assembly a veto.

Mr Bryson had spoken out at a loyalists meeting in east Belfast on Monday night, which was billed as a protest for those who will "not tolerate an economic united Ireland". A poster plugging the meeting described the new bill as a "betrayal act".

READ MORE: Loyalists in Northern Ireland 'will not tolerate' Boris Johnson's 'betrayal act'

Mr Bryson said after the meeting that anger in the loyalist community had reached "boiling point" over the Prime Minister's deal.

HeraldScotland:

The anger is around claims Boris Johnson has ignored Democratic Unionist Party objections and negotiated a Brexit deal that would create a customs border down the Irish Sea, and mean Northern Ireland firms will have to submit customs declaration forms for goods heading to the rest of the UK.

Many unionists inside and outside the party fear for Northern Ireland’s position in the United Kingdom.

Mr Bryson’s lawyers wrote to the Government warning that their client “is gravely concerned with the Prime Minister’s 11th hour retreat from previously stated policy that Her Majesty’s Government would not allow the creation of a border in the Irish sea".

The pre-action letter accuses Mr Johnson of erecting an economic barriers between Northern Ireland and Great Britain.

It says: "The applicant asserts that the deal reached with the EU27 member states is an affront to this country's constitutional sovereignty and its ability to determine its own in country movement and trade."

His lawyers argue that the consent of the people of Northern Ireland is required before any constituional change is "effected much less imposed on this region alone".

READ MORE: The four key Northern Irish elements in Boris Johnson's new Brexit deal 

The letter goes on: "The applicant asserts that the measures are offensive to him as a unionist in Northern Ireland as they fundamentally undermine his position within the union and prevent him from enjoying the right to be treated equally as an equal partner with the people who reside in Great Britain.

"The applicant asserts that this threatens his right to self-identify as British in any meaningful way in circumstances where he will be treated for all relevant purposes as separate and Irish.

"Lastly, just as a hard border on the island of Ireland was seen as a threat to peace and stability in Northern Ireland, the applicant asserts that this threat also results from placing a hard border in the Irish Sea.

"The applicant asserts that these proposed arrangements threaten the respect and equality of the unionist community and create an obvious threat to the peace process."