Its custodians hope to raise £6m to upgrade accommodation for visiting pilgrims, build new accommodation for the disabled, a retreat centre and wet weather cloister.

They raised £400,000 last year, much of it from donations from visiting worshippers, who come on pilgrimmages from across the UK and further afield.

Now shrine rector Mgr John Armitage has revealed that the appeal has received £4m from an un-named benefactor.

'In a very short period of time great things can happen,' he said. 'When I left on December 28 for my holidays I did not expect that when I came back I would bring £4 towards the building fund.

'We have been greatly blessed that a donor has given to the building fund this remarkable sum of money.

'That means with the money we raised last year, instead of £6m to raise, we now have £1,600,000, which is much easier to say than £6m. It's a great blessing on the shrine.'

In an address broadcast online, Mgr Armitage asked worshippers to pray for the donor, who he said was currently unwell.

'Please pray for our donor and pray for all those who come to the shrine and who generously support the work of the Shrine of Our Lady of Walsingham,' he said.

The shrine dates back to the 11th Century, when the Virgin Mary is said to have appeared in a vision to the then lady of the manor, Richeldis de Faverches.

It was designated a minor basilica by Pope Francis in December.

The designation is given by the Holy Father to places of worship which are of particular historical significance.