The UK has been warned not to expect trade talks with the European Union to commence this autumn, based on the current rate of progress of the Brexit negotiations.

Miro Cerar, the prime minister of Slovenia, told the Guardian that the opening round of talks over the terms of Britain's departure from the EU has yielded slower progress than might have been hoped for, due in part to unrealistic expectations and proposals from a British perspective.

Mr Cerar is one of the 27 EU heads of state who will be asked in October as part of the European Council to decide whether sufficient progress has been made on key issues to allow the scope of negotiations to be expanded to include a future UK-EU trade deal, with the Slovenian leader saying it is not likely that this will be the case.

Since the negotiations started, the EU has been adamant that the UK must come to an agreement on the future rights of European citizens, the status of the Irish border and the financial Brexit settlement before any trade talks can begin, while British ministers have been keen to push for these discussions to happen simultaneously.

Mr Cerar said: "What is important now is that the three basic issues are solved in reasonable time. Then there will optimism on realistic grounds. I know this issue of finance is a tricky one, but it must also be solved, along with the rights of people."

The pressure is now on British negotiators to find a mutually acceptable solution to these issues, as any further delays to the commencement of trade discussions increases the likelihood that the UK will not have an EU trade deal in place - whether transitional or permanent - by the time it departs the union in March 2019. This would increase the risk of British businesses being affected by significant tariffs on trade from this date onwards.