Boris Johnson's appointment as Foreign Secretary shows that Britain has "lost its marbles" in the wake of the EU referendum, according to Tim Farron.

The Lib Dem leader, who is attending his second party conference as leader which kicks off today (17 September), is expected to suggest in a speech on Tuesday that Brexit Secretary David Davis will end up resigning from his job.

Farron is also expected to add that the best thing Liam Fox can hope for in his role as International Trade Secretary is to get "a nice tan".

Farron is expected to launch a scathing attack on the 'Band of Brexiteers' in his closing speech to the Lib Dem rally in Brighton on Tuesday.

On Johnson, the Lib Dem leader will say: "Despatched by the PM [Theresa May] to go on tour to as many capitals as possible, because she was concerned that following the referendum, other countries might think Britain had completely lost its marbles.

PMQs
Leader of the Liberal Democrats, Tim Farron MP, will make his comments at the close of the Lib Dem autumn conference on Tuesday BBC

"So she sent Boris Johnson to see them, so that they wouldn't think we'd lost our marbles, they'd now be absolutely certain."

Farron will add: "Liam Fox, the international business secretary.

"Has he read his job description do you think? I'm going to guess that it doesn't include the line 'the post holder should seek to undermine British business abroad and demoralise British business at home'.

"Of course, to be fair, Liam Fox did not undermine British business abroad or demoralise British business at home, because he could only have achieved those things if anyone actually took him seriously. Still, he's getting a nice tan."

He is expected to continue: "David Davis, Brexit secretary. Born again liberal, against ID cards, detention without trial, snoopers charter – all the things that Theresa May is in favour of incidentally. So that'll end well."

On Saturday's agenda, debates will be held on homelessness, corruption and corporate crime, along with consultative sessions on nuclear weapons and sex work.