Prior to the Great Fire of 1666 the old tower had a ring of five bells, a small saints bell and a clock bell. 47 cwt of bell metal was recovered which suggests that the tenor was 13 or 14 cwt. The metal was used to cast three new bells, by William Eldridge of Chertsey in 1672, with a further saints bell cast that year by Hodson. In the absence of a tower, the tenor and saints bell were hung in a free standing timber structure, whilst the others remained unhung.
A new tower was completed in 1704 and it is likely that these bells were transferred to it. However, the tenor became cracked in 1713 and it was decided to replace the bells with a new ring of eight. The new bells, with a tenor of 21 cwt, were cast by Richard Phelps of the Whitechapel Bell Foundry. Between 1714 and 1718 (the exact date of which is unknown), the ring was increased to ten with the addition of two trebles given by two former ringing Societies, the Eastern Youths and the British Scholars. The first peal was rung on 15th Feb 1724 of Grandsire Caters by the Society of College Youths. The second bell had to be recast in 1748 by Robert Catlin, and the tenor was recast in 1831 by Thomas Mears of Whitechapel, just in time to ring for the opening of the new London Bridge. In 1843, the treble was said to be “worn out” and so was scrapped, together with the saints bell, while a new treble was cast by Thomas Mears. A new clock bell was erected in the spire in 1846, provided by BR & J Moore, who had earlier purchased it from Thomas Mears. This bell can still be seen in the tower from the street.
The 10 bells were removed for safe keeping in 1940 and stored in the churchyard. They were taken to Whitechapel Bell Foundry in 1951 whereupon it was discovered that four of them were cracked. After a long period of indecision, fuelled by lack of funds and interest, the bells were finally sold for scrap in 1976. The metal was used to cast many of the Bells of Congress that were then hung in the Old Post Office Tower in Washington.
A fund was set up on 19 September 2005, led by a member of the Ancient Society of College Youths (Dickon Love), with a view to installing a new ring of 12 bells in the tower in a new frame. This was the first of 3 new rings of bells he has installed in the City of London (the others being at St Dunstan-in-the-West and St James Garlickhythe). The money was raised and the bells were cast during 2008/9 by the Whitechapel Bell Foundry. The tenor weighs 26cwt 3qtr 9 lbs (1360 kg) and the new bells were designed to be in the same key as the former ring of ten. They were consecrated by the Bishop of London on 3 March 2009 in the presence of the Lord Mayor and the ringing dedicated on 26 October 2009 by the Archdeacon of London. The bells are named (in order smallest to largest) Michael, Margaret, Thomas of Canterbury, Mary, Cedd, Edward the Confessor, Dunstan, John the Baptist, Erkenwald, Paul, Mellitus and Magnus. The bells project is recorded by an inscription in the vestibule of the church.
The bells are rung every Sunday by the Guild of St Magnus at 12:15. Visiting ringers are made welcome.
The bells are available for visiting bands, quarter peals and peals, on application to the Tower Keeper, Dickon Love [email firstname.lastname@example.org].
Ringing of the bells may be booked privately by Livery Companies, businesses or individuals for their own services in the church, or to mark any other occasion that may wish to be raised.
The bells are maintained by the Ancient Society of College Youths.
A Fraternity was founded in 1343 for the purpose of singing the hymn Salve Regina – a practice that was repeated in a number of other churches of medieval London.