Paul Nuttall quit as UKIP leader after the general election, which saw UKIP's vote share shrink to 1.8% at the general election from 12.6% in 2015 - the year before the United Kingdom voted to leave the European Union.
At the 2015 general election, Ukip won an extraordinary 13 per cent of the vote - beating the Liberal Democrats into fourth place - but was left with only one MP, Mr Carswell.
Former UKIP leader Nigel Farage, who led the party's successful Brexit campaign, had warned UKIP would be "finished" if it embraced an anti-Islam platform.
Phil Hornby spent the day on the English Riviera, and watched the build-up to an unexpected result.
Bolton's election comes as a surprise as the party's deputy leader Peter Whittle and anti-Islam candidate Anne Marie Waters were considered the favored options, Business Insider reports.
The announcement was made at the party's conference in Torquay.
Ukip grandee Nigel Farage welcomed his appointment as party chief, calling him a "man of real substance".
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"The nature of Islam and the practices are such that they tend to have a more dominating effect in a community where there's a large Muslim population than the Christian community", he said.
A banner was superimposed with an image of Mr Farage posing as Adolf Hitler with the European Union logo in the background.
A former soldier and police officer, Bolton won a tight seven-way race, taking 29.9% (3,874) of the overall votes.
Indeed, Mr Bolton had said that UKIP was in danger of becoming the "UK Nazi Party" if it plumped for Ms Waters (Ms Waters herself has vigorously denied this sort of claim).
'Brexit is our core task, ' he told party supporters on Friday at UKIP's conference in southwest England.
UKIP has no remaining MPs in the British parliament and lost all council seats bar one across the country in the last local elections.
"Without being united, we can not lead", he said.
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