The tower is probably the oldest part of the church and is capped by a shingle spire to which a weather vane (in the shape of a cockerel showing the date of 1772) has been added.

The window on the north wall was blocked in when the new vestry was added in 1846 and although the arch above the west door is original, the inner part of the tower arch has been restored.  Until the restorations of 1878, in addition to the gallery that was previously above the south aisle (as described on pages 4 & 5), there was also a gallery in the tower.  The choir used this gallery prior to its removal, and is where the organ pipes are now situated.

There were originally five bells in the tower dating from 1737 that were made by Samuel Knight, Bellfounder, who had a family business in Reading until 1739.  A sixth bell (made by T Mears of the well-known Whitechapel Bell Foundry) was added in 1810.

The lightest bell (the Treble) weighs three-and-a-half hundredweight (approximately 180 kg) whilst the heaviest (the Tenor) weighs eight hundredweight (approximately 400 kg).  Other bells cast at the Whitechapel Bell Foundry include the Great Bell of Westminster (“Big Ben”), “The Clock Bells” at St Paul’s Cathedral and “Great Tom” at Lincoln Cathedral.

It is believed that the clock on the west face of the tower was originally from Rottingdean and was installed by Mr Funnell who had a shop in East Street, Brighton.

A much fuller account about history of the village of Chailey, including St Peter's Church, is available in an excellent book entitled "Chailey through the Centuries" written by Revd Edwin Matthias, a past Rector of the parish.