The Olympia Rally of 1934, in which a number of anti-fascist protestors were attacked by the paramilitary wing of the BUF, the Fascist Defence Force, isolated the party from much of its following.

The party's embrace of Nazi-style antisemitism in 1936 led to increasingly violent confrontations with anti-fascists, notably the 1936 Battle of Cable Street in London's East End.

The party was finally banned by the British government on 23 May 1940 after the start of the Second World War, amid suspicion that its remaining supporters might form a pro-Nazi "fifth column".

He spent the summer that year writing a fascist programme, The Greater Britain, and this formed the basis of policy of the BUF, which was launched on 1 October 1932[27] at 12 Great George Street in London.

[31] The BUF did elect a few councillors at local government level during the 1930s (including Charles Bentinck Budd (Worthing, Sussex), 1934; Ronald Creasy (Eye, Suffolk), 1938) but did not win any parliamentary seats.

[36][37] Having lost the funding of newspaper magnate Lord Rothermere, that it had previously enjoyed, at the 1935 general election the party urged voters to abstain, calling for "Fascism Next Time".

[citation needed] Towards the middle of the 1930s, the BUF's violent clashes with opponents began to alienate some middle-class supporters, and membership decreased.

At the Olympia rally in London, in 1934, BUF stewards violently ejected anti-fascist disrupters, and this led the Daily Mail to withdraw its support for the movement.

[42] The BUF became more antisemitic over 1934–35 owing to the growing influence of Nazi sympathisers within the party, such as William Joyce and John Beckett, which provoked the resignation of members such as Robert Forgan.

This antisemitic emphasis and these high-profile resignations resulted in a significant decline in membership, dropping to below 8,000 by the end of 1935, and, ultimately, Mosley shifted the party's focus back to mainstream politics.

In 1937, William Joyce and other Nazi sympathisers split from the party to form the National Socialist League, which quickly folded, with most of its members interned.

Mary Sophia Allen OBE was a former branch leader of the West of England Women's Social and Political Union (WSPU).

At that meeting Mosley announced that "he was glad indeed to have the opportunity of introducing the first candidate, and ... [thereby] killed for all time the suggestion that National Socialism proposed putting British women back into the home; this is simply not true.