Campbell's move south followed the £30.7m switch of Bulgarian striker Dimitar Berbatov to Old Trafford.

Earlier in the day Hull's pursuit of Campbell had appeared to be placed in jeopardy in the wake of the shock takeover at Manchester City.

The European champions had seemed ready to sell Campbell to the Tigers for £7m providing they secured the services of Berbatov. However, in a twist to the plot, neighbours City threatened to hijack the Berbatov deal by agreeing a £30m transfer fee with Tottenham as a result of a cash injection from new Arabian owners.

The news left Hull chairman Paul Duffen and manager Phil Brown sweating on Campbell's destination and, subsequently, another deal was lined up and concluded for striker Daniel Cousin from Scottish side Rangers

Cousin, 31, joined Rangers from French club Lens in a £1.1m deal last summer and was the subject of a £3m bid from Fulham before the end of his first season in Scottish football.

He scored the opening goal for Rangers in Sunday's Auld Firm victory over Celtic, but was later dismissed for two bookable offences.

Fulham tried to buy the Gabon international during the January transfer window, but fell foul of FIFA rules, which prevent a player representing more than two clubs in one season.

As the midnight deadline approached, reports from Old Trafford had suggested that, following a medical, Berbatov was expected to reject City and opt instead for the lure of Champions League football at United.

So it proved, but in an astonishing development City then announced they had signed Chelsea target Robinho, the 24-year-old Brazilian moving to Eastlands for £32.4m.

Manchester City's financial future had been the subject of intense speculation over the last few weeks after a warrant was issued for the arrest of club chairman Thaksin Shinawatra.

The former Thai president failed to appear in court to face corruption charges and his Thai assets, believed to be worth £800m, were frozen.

Shinawatra spent just 12 months in charge of the Premier League club, but provided a multi-million pound transfer kitty for Sven Goran Eriksson.

Former England coach Eriksson was, however, sacked in the summer and replaced by Blackburn Rovers manager Mark Hughes – a hero across the city after spending the best days of his playing career with United.

According to Al-Fahim, the Manchester City takeover deal will "solve all the club problems" and "clear any pending payments" as well as "bringing the best football players in the world" to the club.

The deal, worth an estimated £150m, would give "all management rights" of the club to new owners, the Abu Dhabi United Group, while Shinawatra would become honorary president of the club "without any administrative responsibilities".

It was reported that ADUG had signed only a memorandum of understanding – essentially a gentlemen's agreement – with City, but intended to completely buy out the club. A period of due diligence for all parties, including the Football Association and Premier League, has commenced.

Manchester City's unexpected cash injection provided not only the funds to threaten United's deal for Berbatov, but, indirectly, appeared to undermine Hull's bid for England Under-21 international Campbell.

Hull had been chasing Huddersfield-born Campbell since the end of his impressive loan stay with the club last season and submitted a club record offer of £7m for his services at the weekend.

The need for Brown to splash more cash if Hull are to survive in the top flight had been underlined by a humiliating 5-0 home defeat against Wigan at the weekend. Eight new players have joined the club since the end of last season, but only one, Geovanni, started.

Sunderland defender Paul McShane signed on loan for Hull on Saturday but too late to play and Brown strengthened his defensive options further yesterday with the season-long loan of Guinea international Kamil Zayatte from Swiss side Young Boys of Berne.

Zayatte, 23, had been on trial with Newcastle last week and was also attracting interest from Everton. He played for Guinea in the Africa Cup of Nations, and is comfortable at right-back, centre-back or in a midfield holding role.

In a separate move, Hull abandoned a proposed deal for Fulham's Seol Ki-Hyeon due to complexities obtaining a new work permit for the South Korean international.