Artist's impression of the sculpture (Picture: Gresleyduck.org

A bizarre disagreement over whether to include a mallard in a sculpture of one of Britain's great railway pioneers has erupted into a vicious row within the society that bears his name.

The chairman of the Gresley Society accused "unbalanced duck fanatics" of going against the wishes of the acclaimed engineer Sir Nigel Gresley's surviving relatives.

The society, which has about 500 members, commissioned sculptor Hazel Reeves to design a statue of Sir Nigel to be unveiled in King's Cross next April, to mark the 75th anniversary of his death.

Ms Reeves included a duck at the engineer's feet to represent his greatest engineering achievement: the Mallard locomotive which hit speeds of 126mph in 1938, still a record for a steam engine.

Sir Nigel was also known to enjoy feeding the ducks at his home in Salisbury Hall, near St Albans in Hertfordshire. Last November, the design (pictured) was unveiled to wide acclaim.

But subsequent complaints from the engineer's grandsons that the duck "demeaned" the engineer prompted a U-turn from the society's council, who conceded that they should have consulted the family before publishing the design.

The duck was removed from the plans - and three council members who had been working on the project resigned.