A dominant feature of the Old Town skyline was being scaled by two expert climbers today in a bid to find out why the roof is leaking.

Christ Church, on Crick-lade Street, is 149 years old next week and parishioners are hoping it will be in tip-top shape for the big celebrations of its 150th anniversary next year.

In a bid to make sure there are no problems next year two expert climbers are scaling the outside of the church wall.

For around five years there has been a problem with water leaking into the belfry of the church and the parishioners decided earlier this year to have a Swindon architects' firm examine the problem.

Terry Hopegood, of Wyvern Architects, has scoured the belfry from the inside and outside with a pair of binoculars.

He said: "You can sometimes see water actually leaking into the belfry from the spire.

"We decided to get the firm WallWalkers to come in and take look at the outside of the church to see what the problem is, and see if there is a problem with stonework on the outside of the building."

WallWalkers is a specialist firm which provides a service to people who need to get to parts of buildings which are normally inaccessible, for examination and work.

Norman Stainer, the owner of WallWalkers, and his colleague Chris Milford, are the climbers who will be dangling 100ft in the air from a rope attached to the tower of Christ Church. The spire itself is 123ft.

The inspection of the tower was taking place this afternoon.

Mr Stainer and his colleague were taking a video camera with them

The footage they shot of the church belfry was being directly relayed below, via a live-link, to where members of the parish and Mr Hopegood were able to see the problems in the tall tower.

If there is major damage to the stonework of the church it could cost thousands of pounds to repair due to the high cost of erecting scaffolding on such a high building.

Mr Stainer, an experienced climber, said: "The architect is very concerned about the condition of the upper belfry, but it is very difficult to assess how urgent the repairs are from the ground.

"Wallwalkers were called in to carry out the detailed video survey, which they can then study in safety.

"The alternative would have been to set up scaffolding which would have taken a lot longer and cost them more money."

Parish administrator, Elsa Palmer, said the details of the celebrations for next year will be announced by vicar the Reverend Simon Stevenette on the 149-year anniversary.

She said: "We are looking at the problems there are in the tower now so that the church is kept in a good condition and we have something to hand over to the next generation."