On 11 December 1170 Archbishop Thomas Becket preached at the Priory of St Mary Overie - which is now Southwark Cathedral.
This was to be the final sermon he preached in London as he was subsequently martyred in Canterbury Cathedral on 29 December.
The Most Revd and Rt Hon Justin Welby. Archbishop of Canterbury, will preach at this service of Choral Evensong.
Also at the service will be the Dean of Canterbury, the Very Revd Robert Willis and representatives from St George's Cathedral, Southwark.
The service will also be streamed on YouTube and Facebook.
For the latest local news and events direct to your inbox every Monday, you need our weekly email newsletter SE1 Direct.
7,000+ locals read it every week. Can you afford to miss out?
Read the latest issue before signing up