Scotland's richest man last night folded his hand in a high-stakes game of poker with Tesco for control of Dobbies Garden Centres.

The supermarket giant called the bluff of Ayrshire entrepreneur and philanthropist Sir Tom Hunter, and now looks set to walk off with the jackpot.

Tesco, which to date has failed to win enough shareholder backing for its £155.6m takeover of Dobbies, now remains the only offer on the table, and yesterday it extended its offer deadline for a second time since launching a 1500p-per-share bid.

Tesco now has until August 19 to gather the required support of more than 50% of Dobbies shareholders to succeed.

To date, the supermarket giant has gathered just 32.6% of shareholder backing for its bid, including its own 11.7% stake and an option to acquire 16.4% of management shares that has now been exercised.

Before Tesco's bid, Hunter was already a significant shareholder in Dobbies, but he has been increasing his holding steadily to 26%.

Hunter's West Coast Capital investment vehicle pitted itself against Tesco in June, raising its Dobbies stake and indicating it might bid.

Hunter paid as much as 1845p per share for some of his holding.

Nonetheless, Hunter, through West Coast Capital, last night made his dramatic announcement to the London Stock Exchange that he had decided not to bid against Tesco for the chance to buy Dalkeith-based Dobbies.

Last night's move may have marked the final play in the high-stakes poker game of bluff and double bluff for the business founded in 1865 by Renfrewshire policeman James Dobbie, who grew a giant leek in his back garden and went on to launch a hugely successful seed enterprise in Kent and Essex.

Hunter had been told earlier this week by the Takeover Panel that he had until 5pm yesterday to "put up or shut up". Last night, the entrepreneur decided to "shut up".

Hunter said the decision not to put in a counter-bid was the result of agreements entered into between Dobbies and Tesco, after the Dobbies board recommended Tesco's 1500p-a-share offer on June 8.

These agreements gave Tesco the right to raise its offer if a rival bid came in, options over some of the directors' shares, and restricted Dobbies in soliciting competing offers, Hunter said.

He added that he still did not think the Tesco offer reflected the long-term value potential of the UK's third-largest gardening centre chain, and that he reserved the right to make another offer if there was "a material change in circumstances".

Hunter also said West Coast Capital did not accept Tesco's offer for the company, and that he had no intention of selling his 26%.

However, one observer close to the Hunter camp last night added that the entrepreneur was now "looking forward to working Tesco to build the Dobbies business - as a major shareholder".

A Tesco spokesman last night said: "We would prefer, of course, to have 100% shareholder support, but we are still delighted with Sir Tom's decision."

Hunter's interest in Dobbies stems from his other gardening business interests. Last year, a consortium led by Hunter acquired Wyevale Garden Centres, the UK's largest garden centre operator, for £311m, then earlier this year he purchased Blooms of Bressingham for £30m.

He also has a 29.9% stake in Flying Brands, the Jersey based home shopping group that owns Flying Flowers.

Meanwhile, Dobbies at last urged its shareholders to accept Tesco's offer.

James Barnes, chief executive of Dobbies, last night insisted: "We now have one offer on the table at a stonk-ing, great price. At 41 times earnings, it is probably the highest offer ever made for a retail group in those terms.

"To tell you the truth, I'm a bit disappointed at Sir Tom Hunter's suggestion that the Tesco offer is not the best for Dobbies shareholders.

"Quite frankly, we have been in communication with Sir Tom and West Coast Capital for 18 months, and they have had ample opportunity to come up with a bid."

He added: "When we last met with West Coast Capital, in January and February, we got the message that it was a case of don't call us, we'll call you'.

"Shareholders now have a clear choice - Tesco or limbo, a situation where Dobbies shares will probably simply flounder if Tesco doesn't win the required 50% support."

Tesco has said it wants to build the Dobbies chain, with 21 stores, into a national brand.

It also sees Dobbies as a means to tap the UK's "green" market, with the sale of environmentally-friendly products like wind turbines, ground-source heat pumps and personal carbon footprint calculators.

Dobbies shares closed down 27.5p at 1625p, while Tesco ended 6.5p lower at 424.75p.