The former Thai premier had insisted that he should be consulted on the identity of Stuart Pearce's successor and was behind an unsuccessful approach to former Chelsea boss Claudio Ranieri, who opted instead to take up the vacancy at Juventus.

But with Thaksin's ability to finance a takeover now in doubt as a result of moves by anti-corruption investigators to freeze his assets, City are pushing ahead with efforts to persuade Sevilla boss Juande Ramos to move to England.

Former Alkmaar and Porto coach Co Adriaanse, currently out of work, appears to be the most likely back-up option as Ronald Koeman has indicated that he will see out the remaining year on his contract at PSV Eindhoven.

There has also been speculation about a possible bid to lure former Manchester United striker Mark Hughes away from Blackburn.

Capturing Ramos would represent a major coup for City. Under his management, Sevilla have won back-to-back UEFA Cup titles and he could yet claim a domestic league and cup double this season.

A City source said a decision on the new manager could come within days as the club desperately attempts to avoid a scenario in which players return for pre-season training with no manager in place.

"There is a need now to move quickly," the source said. "We could even see an announcement within the next seven days."

City chairman John Wardle is meanwhile expected to give the Thaksin camp several days to provide assurances that the proposed deal can go ahead.