"It is with great sadness that we announce that Paddy Ashdown passed away earlier this evening following a short illness", the political party said on its Twitter blog.
According to the party, Ashdown will be desperately missed by his party colleagues.
"Paddy will be… remembered as someone who made an immeasurable contribution to furthering the cause of liberalism", the Lib Dems stressed.
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In early November, Ashdown revealed he was suffering from bladder cancer.
Ashdown led the Lib Dems between 1988 and 1999. After leaving the party, Ashdown continued to perform public activities and engaged in writing.