Britain clinched a Brexit deal with the European Union (EU) on Thursday, European Commission President Jean-Claude Juncker said, just a few hours before the start of a summit of the bloc's leaders in Brussels.

Separately, British Prime Minister Boris Johnson said “we have a great new Brexit deal”.

“Where there is a will, there is a deal — we have one! It's a fair and balanced agreement for the EU and the UK and it is testament to our commitment to find solutions,” Juncker tweeted. “I recommend that EUCO endorses this deal,” he said, referring to the European Council of the leaders of member states that was to meet later Thursday.

“We've got a great new deal that takes back control,” Johnson said in his tweet on the matter. “Now parliament should get Brexit done on Saturday so we can move on to other priorities like the cost of living, the NHS, violent crime and our environment.”

Britain and the European Union have been racing to renegotiate the Withdrawal Agreement in time for an Oct 31 Brexit.

Juncker said in a letter that he would recommend that the leaders of the other 27 member states approve the deal, adding it was “high time” to complete the divorce process and move on as swiftly as possible to negotiations of the EU's future partnership with Britain.

Johnson is hoping to get approval for the agreement in a vote at an extraordinary session of the British parliament on Saturday, to pave the way for an orderly departure on Oct. 31.

However, the Northern Irish party Johnson needs to help ratify any agreement has refused to support the deal, which was hammered out over weeks of negotiations.

A Democratic Unionist Party source told AFP the party's earlier statement that it could not support customs and consent issues, as well as sales tax arrangements, “remains our position”.

Meanwhile UK's opposition Labour Party leader Jeremy Corbyn has said the best way to get Brexit sorted is to give the people the final say in a public vote.

The pound surged more than 1 per cent and British share prices rallied after the announcement that an agreement had been reached.