More than 150 political portraits which belonged to the late Lord Stratford, Tony Banks, go under the hammer in May.
This painting of Henry Fox is among the more expensive items
Styles range from classical portraiture to outrageous caricature with values from a few hundred pounds to £120,000.
The former Labour MP for West Ham collected portraits of politicians from the 18th Century to modern times, from drawings to paintings and marble busts.
As chairman of the Parliamentary Works of Art Committee, he also influenced the Palace of Westminster's collection.
Among the most expensive items is a portrait by Sir Joshua Reynolds of Henry Fox, the father of one of Lord Stratford's favourite characters, Britain's first foreign secretary Charles James Fox, expected to fetch between £80,000 and £120,000.
Others include an 18th Century oil painting of Charles James Fox by Sir Henry Raeburn, valued at between £20,000 and £30,000.
And a cartoon by Dave Brown from 2001 showing the larger-than-life sculpture of Margaret Thatcher commissioned by Mr Banks towering over MPs in the House of Commons lobby, is expected to fetch between £500 and £700.
His collection, ranging from traditional oil paintings to cartoons, will be sold off at Bonhams' salesrooms in New Bond Street, London, on 3 May.
Among his favourite political characters, were anti-slavery campaigner Charles James Fox and William Pitt the Younger.
"From the collection, one can see that Banks was fascinated by the 18th Century," said Camilla Seymour, Bonhams' head of portrait miniatures.
"He appears to have loved its robustness and the way politics then were characterised by the combination of oratory and personal confrontation that he also revelled in. "
Before he stood down as an MP for West Ham at the 2005 election, Mr Banks said he would not miss the "tedious" constituency work, but would miss his art committee role, looking after historic paintings and sculptures in Westminster.
He said he found the job "straightforward fun" which gave him "intellectual enjoyment".
A colourful and outspoken character at Westminster, Mr Banks died suddenly from a stroke, while on holiday in the US in January 2006.