Plans for a monument in Whitehall to honour World War II heroines is in trouble after major gas pipelines were found under the proposed site.
The memorial for WWII heroines is expected to be unveiled on 9 July
The Women of World War II Memorial Fund has been told it will cost £335,000 to remedy the problem, which the charity says it cannot afford.
Westminster Council is deciding if it can be moved to Parliament Square.
The £1m memorial is expected to be unveiled in July to mark the 60th anniversary of the end of WWII.
But Betty Boothroyd, the charity's patron and former Speaker of the House of Commons, said: "The Queen has accepted our invitation to unveil the monument on 9 July and our plans for a reunion of war heroines and veterans are well-advanced.
"It would be a tragedy if all our hard work and high hopes are jeopardised by a technical hitch."
Transco, the energy company which owns the gas pipes, is giving the charity a £50,000 donation, but says it has to adhere to health and safety regulations to keep a clear access to paths.
But Major David Robertson, the charity's chairman, said they do not have the funds to meet the bill.
"The solution is to move the monument a short distance out of harm's reach. Westminster Council understands the urgency of the problem and is working with us," he said.
"The contribution women made to the war effort has been underrated for the past 60 years."
The bronze memorial, which will be 22ft high, 16ft long and 6ft wide, will depict the uniforms and working clothes worn by women during WWII.
Last year the charity was awarded £934,000 as a "special tribute on behalf of the nation".