Brooks's Club, Westminster, was the main social centre for the Whigs and for a while, the Grenvillites. 

Founded in 1764 as a social and non-political club by William Almack, moving to 60 St James's Street in 1778. It established a reputation for heavy gambling. Among the members were Fox, Pitt, Reynolds, Garrick, O'Connell Horace Walpole, Wilberforce, Palmerston and Hume.

The older Grenvillites, Nugent Buckingham and William Grenville, were not members, though Thomas Grenville was a member from 1779 to 1794. Numerous younger members, however, joined:

• by July 1804: Folkestone, Charles Wynn, Althorp, Laurence
• by 1805: Ebrington
• by 1806: Stafford
• by 1807: Richard Neville, William Shipley, Pascoe Grenfell, Henry Wynn, Essex
• by 1808: William Fremantle, Carrington
• by 1809: Bulkeley
• by 1811: Hereford
• by 1812: Cawdor, Spencer, Grafton (formerly Lord Euston), Newport
• by 1813: Plunkett
• in May & June 1816: Richard Temple, Lord Carysfort, Granville Proby, Lord Fortescue, George Fortescue, Sir George Nugent, Scrope Bernard Morland, Sir Robert Williams.

The Grenvillites withdrew in 1822, when the first Duke gave his support for Liverpool. 

Sources

Sack p 126-7; Weinreb.