An anonymous donor has given £1.5 million in an "ordinary-looking envelope" to Bath Abbey to help with its £18 million restoration scheme.

The donation is the largest the Abbey has ever received from a private individual.

The donor explained that the main reason behind the gift was that he was: "much impressed by the care and the consultation which has been put in by the Abbey, which is such a vital part of Bath's future."

He continues by saying that: "This generation has a solemn duty to ensure the Abbey is fit and able to carry out its service to the city and the community for the next hundred years."

The money will go to the Abbey's £19.3 million Footprint project, aimed at stabilising the building's collapsing floor and introducing an under-floor heating system using Bath's famous hot springs as an energy source. It will also improve the Abbey's visitor facilities.

Laura Brown, Footprint Appeal Director, said: "We are very grateful for this amazingly generous gift from one remarkable individual. It came in an ordinary-looking envelope, without pomp or fanfare, but the contents were just astounding. It clearly demonstrates the strength of feeling that the Abbey and its ministry inspires in people."

The abbey needs to raise £7.1 million in order to receive the full match funding amount of £10 million from the Heritage Lottery Fund. So far, including the mystery donation, it has raised £2.6 million.

Bath is a World Heritage Site and the Abbey, at the heart of the city, is visited by around half a million people every year.