About one million special 50p coins to commemorate Brexit on October 31 were minted, but the government has refused to say how much it cost.
The defunct coins bearing the date will now be “recycled” after the UK’s departure from the EU was delayed by three months.
It also emerged that a thousand trial coins were struck to mark the first exit date of March 29, subsequently missed by Theresa May.
Details of the Brexit coins, carrying the words “Friendship with all nations”, came on the last day of parliament sitting before it broke for the general election.
Responding to a written parliamentary question by former EU ambassador Lord Hannay of Chiswick, Tory frontbencher the Earl of Courtown said: “Approximately one million coins were minted in October to mark the UK’s exit from the European Union, in addition to 1,000 trial coins that were struck before March 29.
“Coins bearing these dates will now be recycled and the value from the materials will be recouped by the exchequer.
“The cost of minting these coins is commercially sensitive.”
Former chancellor Philip Hammond had planned a limited edition of about 10,000 commemorative coins to be sold to collectors for £10 each.
But his successor Sajid Javid pressed for a much greater circulation, portrayed at the time as a statement of intent that the treasury was fully behind Brexit.