The Prime Minister and the Commons Speaker led guests from the worlds of politics and broadcasting at a memorial service for the former Liberal Democrat leader Charles Kennedy.

David Cameron and John Bercow were joined by senior MPs including current Lib Dem leader Tim Farron and his predecessor, ex-deputy prime minister Nick Clegg, at the service.

Journalists Jim Naughtie and Ian Hislop also paid tribute to the former Ross, Skye and Lochaber MP who was nicknamed "chat show Charlie" because of his popularity on TV and radio.

Mr Kennedy, whose passing was marked by a poignant tribute from Scottish Liberal Democrats leader Willie Rennie at the weekend, died in June aged 55 at his home in Fort William after suffering a major haemorrhage as a result of his long battle with alcoholism.

His ex-wife Sarah Gurling and their son Donald were present for the emotional service at St George's Cathedral in Southwark, south London.

Lib Dem peer Lord Jim Wallace described Mr Kennedy as a man of "exceptional character and talent" and praised his "great courage" in speaking out against the Iraq War.

The former Lib Dem leader was also a staunch pro-European and, looking ahead to the EU referendum, the "In campaign will certainly be the poorer without him", Lord Wallace said.

Mr Kennedy was elected aged just 23, defeating government minister Hamish Gray, and made his way to the Palace of Westminster "not without some difficulty", his friend joked.

The young politician's fashion choices shocked Margaret Thatcher, who was heard to remark: "Are you telling me Hamish Gray was defeated by a man who wears white socks?"

He quoted Mr Kennedy's own attitude to Westminster: "Politics is much too serious to be taken too seriously."

Naughtie remembered Mr Kennedy's frequent appearances on BBC Radio 4's flagship today programme, describing him as a "natural" broadcaster even though "sometimes he found himself a little short of a good briefing".

He said Mr Kennedy excelled at "the art of being funny and serious".

Have I Got News For You, the show on which Mr Kennedy was a popular guest and host, was represented by regular team captain Hislop, who read Dylan Thomas's And Death Shall Have No Dominion.

Mr Kennedy's popularity across party divides at Westminster was indicated by the presence of leading Tories including Ken Clarke and Michael Gove, while senior Labour figures at the service included Alastair Campbell - a close friend of the ex-Lib Dem leader, despite their political differences over Iraq.

Mr Kennedy's friend and former brother-in-law James Gurling talked about his love of music - ranging from David Bowie to ex-Spice Girl Emma Bunton.

An excerpt of Bowie's Heroes was played, while the Roman Catholic cathedral's organist played a medley of Mr Kennedy's favourite Frank Sinatra songs Fly Me To The Moon and My Way at the end of the service.