One of Christopher Wren's masterpieces, and at 226ft high his tallest church, St Bride's is a more than 300-year-old, Grade 1 listed structure; however, its status as a working church has hindered its attempts to raise funds.

James Irving, the church's finance director, said: "We've had difficulty so far convincing English Heritage or the National Lottery that its something they'd want to make even a modest grant to. That's not to say that they won't but churches tend not to tick a lot of boxes, although this is a completely secular appeal to preserve the heritage of the building."

Irving added that he envisaged support coming from a group of private and corporate donors, with work due to begin on the damage spire early next year.

The church will officially launch its 'Inspire!' appeal on 21 March, with the aim of raising the £2.5m needed to repair the spire and return it to its former glory, as well as undertaking much-needed work on the church interior.

The venerable David Meara, archdeacon of London and rector of St Bride’s said: "Since renovation work was last carried out almost 70 years ago, the church has survived lightning, acid rain, smoky chimneys and extensive piling, as well as the ever-present birds.

"The falling stonework is now becoming a grave concern and we desperately need these funds. We have committed £300,000 from our reserves, but need more."

A special fundraising Working Group has been set up under the chairmanship of Paul Finch OBE, chairman of the Design Council CABE board. Several events are being planned for 2012 for potential corporate donors, the congregation and general public.

Adrian Tinniswood, the well-known author and historian, will help kick-off the appeal with a lecture at the official launch event.