Nigel Farage has told Daybreak that if the Tories and Labour "do not offer absolute binding promises of a referendum on our future in Europe, the UKIP vote will continue to grow."
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The slump will spark scrutiny, especially as statistics show a rise in racially or religiously motivated offences following the EU vote.
The 53-year-old was killed shortly after leaving her home in Mosta, Prime Minister Joseph Muscat said.
Jordi Sanchez of the Catalan National Assembly and Jordi Cuixart of the Omnium Cultural group were jailed on Monday.