The European Commission will decide this month whether to move on to the next stage of talk between the European Union and Britain as an exiting member state.
And German MEP David McAllister said there is only a 50/50 chance of progression, which would mean barely any progress has been made in a year.
Brussels is stalling over claims Prime Minister Theresa May’s Government has not provided satisfactory offers in three keys areas, including EU citizens rights, the Irish border and the Brexit bill.
Mr McAllister told Robert Peston on his Sunday morning show there remains a chance of talks collapsing if bureaucrats in Brussels are unsatisfied.
He said: “It is very very difficult to predict. I would say at the moment it is still a 50/50 situation.
“We want to see progress – we want to see the next part of the negotiations being started, the clock is ticking, we are all losing time.
“We have a sincere interest in moving forward but once again it is up to the members, the heads of Government of the European Council, to decide whether the sufficient progress has now been made or not.
“I think both sides are working very hard to get a deal, but we are not quite there yet.”
Mr McAllister also claimed talks between Mrs May and European Commission President Jean-Claude Junker in Brussels tomorrow will be crucial.
The MEP and Christlich Demokratische Union Deutschlands (CDU) politician insisted the European Commission will decide if “sufficient progress” has been made when it meets later this month.
He claimed not every element of the three sticking points will need to be in place, but that they must be satisfied with a base offer.
Rumours of an offer for UK commitments to Brussels until 2020 increasing to £60n -from £20bn – have enraged those who say Britain does not “owe” anything.
Foreign Secretary Boris Johsnon said the EU could “go whistle” last year.
But after Brussels put Britain over a barrel and refused to come to the table until they are satisfied, others believe there was no choice but to up the offer.
There is fear of a “no deal” Brexit, which would mean there is not trading partnership with the EU after March 2019.
Elsewhere in the EU businessmen and politicians have urged their leaders to get on with Brexit talks- because of what they have to lose.
In Germany, traders say there must be a deal in place – or they could lose millions in exports to the UK.
Mr McAllister said the EU still does not want Britain to leave – a move which will leave a huge black hole in the joint purse.
He said: “We did not ask for this you want to leave. We deeply regret this but we accept the decision on the UK government.”
It comes as EU official said Mr Juncker and his Brexit negotiator Michel Barnier will meet EU lawmakers early on Monday, in a further sign a Brexit deal with Britain could be ready.
Mr Juncker and Mr Barnier will meet Mrs May over lunch in Brussels on Monday. Diplomats say agreement on three key issues holding up talks on future trade relations is close.
One major hurdle has been European Parliament concerns about the rights of EU citizens in Britain after Brexit.
Mr Juncker’s meeting at 10am GMT with the legislature’s Brexit team, led by Guy Verhofstadt, appears to be an effort to secure approval from Parliament for a deal on citizens’ rights. The parliament must approve any Brexit treaty.