A Royal Parks spokesman said: “Numerous times we have requested assurances from the applicant that they have approval from the family for the statue.

“To date we have not had those assurances.”

The £300,000 work was commissioned by the Public Memorials Appeal, shortly after Lady Thatcher’s death in 2013. But Carol Thatcher, her daughter, sent a letter to the charity last year protesting about the about the absence of a handbag from the statue.

The trust that commissioned the sculpture has admitted Miss Thatcher is “upset” about the lack of a handbag – but has insisted it will fight on to secure permission for the tribute to be exhibited.