He was once described as the most dangerous man in Britain, a speaker so controversial that a lecture he gave in Norfolk resulted in a near riot when sailors attacked him and his audience.

The remarkable life of John Thelwall - and the fateful incident in Great Yarmouth which led to him abandoning politics for years - will be explored at symposium which will examine Norfolk's role as a hotbed of radical thought in the 18th century.

Thelwall was one of the most popular and effective orators of his day, with his style once likened to a ‘volcano vomiting out lava’.

But his opposition to the government's decision to declare war on France in 1793 and his campaign for democratic reform in Britain also won him enemies.

John Thelwall's speech in Great Yarmouth was interrupted by violent sailorsJohn Thelwall's speech in Great Yarmouth was interrupted by violent sailors (Image: Mike Page)

In 1796, he was giving a lecture in Yarmouth when a gang of sailors burst in and violently broke up the meeting.

The sailors, reportedly armed with cudgels and cutlasses, tried to press gang him into the navy and more than 40 people were hurt in the ensuing scuffle.

Norfolk Record Office has recently obtained documents, provided by the John Thelwall Society, describing the events.

Shaken by the violence, not long afterwards, Thelwall retreated to a farm in the Wye Valley with his family, where he wrote poems and a novel.

Before his death, at the age of 69 in 1834, he returned to politics as editor of a journal, which he used to denounce the government for the 1819 Peterloo Massacre.

More than a dozen people, protesting over the right to vote, were killed and hundreds hurt when the cavalry moved to arrest the leaders in St Peter's Field, Manchester.

As well as John Thelwall, the symposium will feature talks on other aspects of 18th century political radicalism - and attempts to suppress it - in Norwich and Norfolk.

A bust of Amelia OpieA bust of Amelia Opie (Image: Norwich Castle Museum & Art Gallery/Norfolk Museums Service)

Norwich's Amelia Opie, a novelist and dedicated campaigner for the underprivileged and against slavery will also be discussed.

The city's Opie Street, between Castle Street and London Street, is named in her honour, while a statue of her sits on one of the rooftops.

Norfolk Record Office at the Archive Centre will host the symposiumNorfolk Record Office at the Archive Centre will host the symposium (Image: Antony Kelly)

John Thelwall and Radical Norfolk: A Symposium runs from 10am to 5pm on Friday, October 25 and will be held at the Norfolk Record Office in the Archive Centre, next to County Hall in Martineau Lane.

Tickets, available from norfolkrecordofficeblog.org/events-summer-autumn-2024/#thelwall, are £25 and holders are also able to view the event online.