If at all, tbh. Even Boris Johnson, someone you'd expect to have a motto or catchphrase, and whose ability as an ambassador and salesman for London has far outstripped his ability as mayor, doesn't have any that I can think of.
You have to remember that unlike certain elements of the American electorate, we in the UK (with the possible exception of a subset of UKIP voters, who are subscribers to the cult of Saint Nigel de Farage) do not revere our politicians or indeed our politics.
We do more of this sort of thing:
https://twitter.com/corbynjokes/status/679682048794177537
You have to remember that unlike certain elements of the American electorate, we in the UK (with the possible exception of a subset of UKIP voters, who are subscribers to the cult of Saint Nigel de Farage) do not revere our politicians or indeed our politics.
We do more of this sort of thing:
https://twitter.com/corbynjokes/status/679682048794177537