Financier Mr Dermot Desmond, who already owns London City Airport, spent more than €10 million (£7.88 million) increasing his stake in the British airports group TBI last week, days before a bid for TBI from French construction group Vinci was withdrawn.

A spokesperson for Mr Desmond would make no comment, but it is understood that he bought 9.2 million TBI shares last Thursday and Friday for £6.2 million sterling (€10.5 million), increasing his stake to 28.4 million shares or 5.08 per cent of the total.

The TBI shares were bought at between 60p and 72p sterling, well below the 90p offer price from Vinci.

Vinci yesterday withdrew its £516 million sterling (€860 million) offer for TBI after it failed to get 90 per cent acceptances for its offer. Vinci ended up with 84 per cent acceptances and could have extended the offer period to get the required 90 per cent. Instead it opted to lapse an offer that was increasingly seen as too high given the crisis in the aviation industry.

Vinci said it had no plans to sell the 14.9 per cent of TBI it bought in the market, but lapsing its current offer means that takeover rules prevent it making another bid for TBI for a year.

TBI owns Luton, Belfast International and Cardiff airports and other airports in Sweden, the US and Bolivia. But TBI was hit badly in August when BMI British Midland pulled out of Belfast International and switched its services to the rival Belfast City Airport.

The withdrawal of the Vinci offer yesterday triggered heavy selling of TBI shares and the shares fell 14p to 44p sterling, with more than 97 million shares trading.

Dealers said that, while there were no obvious indications of any further buying yesterday by Mr Desmond, the sell-off of TBI shares would have given him a golden opportunity to further increase his stake, if that was his plan.

Mr Desmond's resumed stakebuilding in TBI will inevitably lead to speculation on whether he has any plans to bid for the airport operator or form some sort of link-up between his own London City Airport and TBI.

He first emerged as a 3.7 per cent shareholder in March last year but has not been involved in any further buying of TBI shares until last week's purchase of 9.2 million shares.

Any other bidder for TBI will need to get the support of Vinci and its 14.9 per cent stake - bought at 90p sterling a share.