Uefa are still ironing out problems over their proposed switch of the Champions League final from Covid -hit Istanbul.

Manchester City and Chelsea are both still waiting to hear whether the game will be moved to Portugal - currently favourite to stage the May 29 showpiece - or whether a different solution will be found.

Negotiations between Uefa and the UK government appear to have hit stalemate over the football body’s need to fly in staff and officials from all over Europe to run the final, and of broadcasters and other media from around the globe to screen it.

The problem arose last Friday, when Turkey was placed on the government's travel “red list” of countries with high Covid-19 infection rates.

The original plan was for 4,000 fans of both City and Chelsea to be allowed to attend the final, the first in the Blues’ history and only a third for the Londoners, in Istanbul.

But the red list designation would have made that virtually impossible, and the requirement that players and officials returning from the final might need to quarantine in hotels for two weeks also threatened the European Championship, due to start two weeks after the Champions League final, on June 11.

The UK government made moves to have the final switched to Britain, with Wembley, Villa Park, Cardiff’s Millennium Stadium and Glasgow’s Hampden Park all mooted as possibilities.

The English Football League was prepared to be flexible over the use of Wembley for their play-off finals that weekend, and that switch would have allowed around 4,000 fans of both clubs to attend.

But Uefa stressed the need to accommodate staff, officials and media as well as supporters, and have sought an alternative.

Portugal is top of their list, with the Estadio Do Dragao - home of Porto - being made a firm favourite.

Uefa staged the later stages of last season’s tournament - also hit by Covid - in Portugal in August.

Estadio do Dragao, the home of Porto

The announcement of the country on the UK “green list” - which would mean no quarantine on return to the UK unless a mandatory test proved positive - has boosted Portugal’s chances.

It would mean up to 6,000 supporters of both sides could be allowed to attend, and with the cost of mandatory Covid tests dropping from an average £200 to around £50, the extra cost is no longer prohibitive.

But Uefa sources say that there are obstacles to be overcome, and they are working furiously to try to reach a solution, with the final just 18 days away.

A decision is expected to be made today (Tuesday), and formally announced tomorrow - as long as outstanding issues can be overcome.

Porto, with a 50,000-capacity stadium, has staged the European Super Cup and the final of the 2019 Euro Nations League final, and remains favourite.

But the Estadio Da Luz and Jose Alvalade - the homes of Benfica and Sporting Lisbon which were used for the unique finals tournament in August - are also still on the table.