Paine and Stewart undertook the conservation of the painted decoration in the dome of St Paul’s Cathedral between September 2003 and January 2005. The scheme, executed by Sir James Thornhill between 1714-17, is the largest and one of the most significant church paintings in Britain, being the very first major ecclesiastical scheme enacted after the Reformation.

Covering the entire inner surface of the dome located above the tambour, the decoration is comprised of eight scenes from the Life of St Paul contained within fictive arcading and is executed in oil on plaster in a basso-relievo style. However, the scheme was badly damaged by water infiltration relatively soon after its completion, resulting in an extensive programme of restoration and repainting by E.T. Parris in 1853-6, followed by a further campaign of cleaning and further restoration by Professor E.W. Tristram in 1934-6.

However, seventy years of subsequent exposure to London’s polluted atmosphere saw the requirement to conserve and clean the scheme again and so the dome scheme became a part of the £40m restoration works to clean and reinstate the historic surfaces throughout the inside and outside of the cathedral.

In addition to the work to conserve the dome paintings, Paine and Stewart also re-discovered the original Thornhill painted designs for the tambour that supports the dome (previously over painted in the nineteenth century). Following extensive research they were able to formulate designs that exactly replicated the original 1710 presentation of the tambour: namely, fictive fluted pilasters, foliate swags, and Dean and Chapter crossed swords. The repainting was carried out by Hesp and Jones and Co.Ltd.

The restoration project of the cathedral as a whole was awarded the English Heritage Award for Sustaining the Historic Environment in 2012.