Sir Tom, who owns 29.9 per cent of the chain, is attempting to block an open offer announced by the Midlothian-based group in April to strengthen its balance sheet and fund expansion.

Supermarket giant Tesco owns 65 per cent of the chain after a £155.6m deal last year, although Sir Tom said at the time the deal undervalued the business.

It will cost Sir Tom's West Coast Capital (WCC) investment vehicle around £40m to take up the extra shares and maintain its stake in the business. If it does not, WCC's holding could fall to around 15 per cent.

Sir Tom is seeking an interim order to block the proposals, although Dobbies said it would defend its plans at a hearing."

The garden centre chain has around £110m in debt and is looking for funding to expand beyond the 23 sites which it has at the moment.

Tesco is underwriting the offer, which means it will buy up any of the new shares not taken up by existing investors.

A WCC spokesman said: "We do not believe that this offer is in the best interests of shareholders, in particular minority shareholders."