The chapel, dedicated to St Giles, is a small stone structure, originally erected in the 12th or 13th century. It was rebuilt in the late 18th century, but the east window belongs to the old edifice. Restoration works took place in 1881, when the chancel arch was raised, the east window filled with stained glass, depicting our Saviour as the Good Shepherd and the Light of the World, the whole church re-floored and re-seated, the chancel re-roofed and an organ chamber and vestry added, at a total cost of £659.
An organ by Forster & Andrews of Hull was installed in 1883 at a further cost of £222, and remains in working order to this day. The nave was further improved in 1886 by the erection of two arcades, thus converting the wide square nave into a nave and two aisles, giving a more ecclesiastical appearance. The sash windows have been removed, and their Gothic heads filled with 14th century tracery. The cost of these various improvements was about £500, which was raised by subscription.
The font dates from the 13th or 14th century.
The stained glass window at the western end of the nave was donated by Jon Henry Burn of Cullercoats in memory of his mother, Barbara Burn, of Netherwitton who died in May 1842. The north window shows St Paulinus Arhieps, St Edwin ree Northumbriae, St Jacobus Diaconus. The south window shows Sanctus Aqidius, Sta Maria Mater Dei, St Aidan Eps. The east window: St John, Jesus the Good Shepherd and St Peter.
The electric organ-blower was installed in memory of Winifred Mary Orde of Nunnykirk, by her children. For many years she was voluntary organist in St Giles Church and died in 1950.
New gates for the churchyard were commissioned and hung to commemorate the second millennium.
In the chancel there is a life-size effigy of a lady wearing a wimple and long-sleeved gown. Her clothing is similar to that of Roger Thornton's wife Agnes, in a brass taken from All Saints' Church Newcastle where they were buried ,and now in St Nicholas Cathedral in Newcastle.
The carving on the pulpit shows St Giles, patron saint of lepers and cripples. St Giles was an abbot born in Athens, Greece, and his festival is celebrated on 1st September.