As Catalonian leaders signal they could declare independence from Spain within a week, former UK Prime Minister Tony Blair is reportedly pitching himself as a mediator between the two sides.

The former Labour leader reportedly believes he can help bring the Catalan administration led by Carles Puigdemont and the conservative leadership of Mariano Rajoy in Madrid together, the Daily Express reports.

The situation in the northeast of Spain deteriorated over the weekend when police attacked voters casting their ballots in a referendum deemed illegal by the nation’s Supreme Court.

Spanish authorities failed in their attempts to stop the vote going ahead, and their actions only entrenched divisions. Catalan officials claim 90 per cent of people voted for independence, although the fairness and turnout of the vote have been questioned.

Mr. Blair considers himself an expert negotiator following his involvement in the Good Friday talks in Northern Ireland as well as being a Middle East envoy for the United Nations.

A man dressed in the Catalonian flag confronts officers as police move in on the crowds as members of the public gather outside to prevent them from stopping the opening and intended voting in the referendum at a polling station where the Catalonia President Carles Puigdemont will vote later today on October 1, 2017 in Sant Julia de Ramis, Spain. (David Ramos/Getty)

His critics, however, point out that despite holding the UN post for almost eight years, he has failed to secure any real progress in the peace process between Israel and Palestine.

UKIP senior figure Ben Walker said the idea of Tony Blair mediating over Brexit talks “meant the process would become as fair as a 17th-century witch trial”.

He told the Express: “Tony Blair is an EU fanatic who will do whatever Brussels wants – which in this case is to ignore the wishes of the people of Catalunya.

“It will be more Auto da Fe than Fair Hearing.

“He will take the side of the Spanish government and conveniently ignore the fact the Spanish Constitutional Court is not neutral and does the bidding of the government.

“It is no good anyone just sitting back and condemning the actions of the Guarda Civil: this is about the issue of self-determination and Rajoy is just not listening.”