LONDON, Aug 19 (Reuters) - British Prime Minister Boris Johnson wrote to European Council President Donald Tusk on Monday to propose replacing the Irish backstop with a commitment to put in place alternative arrangements by the end of a post-Brexit transition period.
In the letter, published by his office, Johnson repeated his calls for the backstop - an insurance policy to avoid the return of a hard border on the island of Ireland - to be removed from the deal the EU reached with his predecessor Theresa May.
Johnson, who has promised to take Britain out of the EU on Oct. 31 with or without a deal, said that he believed it was possible to reach an agreement and that doing so was his government's "highest priority".
"The UK and the EU have already agreed that 'alternative arrangements' can be part of the solution. Accordingly: I propose that the backstop should be replaced with a commitment to put in place such arrangements as far as possible before the end of the transition period, as part of the future relationship," he wrote.
Johnson added that Britain was ready to look "constructively and flexibly" at what commitments could help provide confidence about what would happen if such arrangements were not fully in place at the end of that period.
The backstop would force Britain to obey some EU rules if no other way could be found to keep the land border open between British-ruled Northern Ireland and EU member Ireland. Dublin says this is crucial to maintaining peace on the island.
In his letter, Johnson said the backstop was "simply unviable" because it is "anti-democractic and inconsistent with the sovereignty of the UK as a state" but that he was committed to ensuring there was no return to a hard border.
"The government will not put in place infrastructure, checks, or controls at the border between Northern Ireland and Ireland. We would be happy to accept a legally binding commitment to this effect and hope that the EU would do likeswise," Johnson wrote.
The EU has so far said the withdrawal deal cannot be renegotiated. Johnson is due to carry out his first foreign trip as prime minister this week to meet with German Chancellor Angela Merkel and French President Emmanuel Macron.
"Time is short. But the UK is ready to move quickly, and, given the degree of common ground already, I hope that the EU will be ready to do likewise," he wrote to Tusk. (Reporting by Kylie MacLellan; Editing by Hugh Lawson)