Their arrival back in the UK came as Opik announced he would be launching a campaign to succeed Boris Johnson as mayor in 2012.
The former MP, who lost his seat at the last election, will be knocking on doors today in a bid to boost his profile as part of a council by-election campaign in Southwark.
Among his list of policies, he will propose the Tube runs 24 hours a day, more help for small firms to compete against large businesses and tougher action to halt the epidemic of roadworks.
Mr Opik was among several people who put themselves forward for a mayoral shortlist last year but Lib-Dem chiefs postponed any selection decision in autumn.
