It was a city Prime Minister Lee Hsien Loong first visited at age 17, and 45 years later, the city of London made him one of its own, presenting him with the honour of being a "freeman" with its Freedom of the City award.
At an elegant ceremony comprising top business leaders, financiers and academics, Mr Lee was given a scroll of the award by the Lord Mayor Fiona Woolf.
She called on him to see Mansion House, the official office of the city of London, as his "home away from home" where he would always be welcomed as a friend.
The occasion was especially meaningful because it was in the same room 32 years ago that then-PM Lee Kuan Yew was accorded the same honour.
Ms Woolf harked to the historical and close ties between Singapore and Britain. Just as in the speech honouring the elder Mr Lee then, Ms Woolf recalled the special relationship Mr Lee had in having studied at Cambridge, where some of the city's freemen were from, and some of Britain's brightest minds hailed from.
She also reminded the audience, which included Mr Lee's former tutors from Cambridge, that he was a Cambridge "wrangler" - someone with first-class honours in mathematics in two, instead of the usual three years.
When the elder Mr Lee received the award, then lord mayor Sir Christopher Leaver, remarked that "as a young man, you chose as your theme and slogan, one word "Merdeka", which can be interpreted in English as "Freedom". He spoke of Mr Lee's efforts to transform a young nation.
On Facebook after the event, PM Lee dedicated the award to Singaporeans, especially the pioneer generation.
He also said London held many happy memories for him. Mr Lee brought smiles all round during his speech when he said that when he first visited, the city "was the capital of cool" in the swinging sixties, but he stayed "sober" nonetheless and enjoyed the plays and concerts, and visiting museums and the "greatest bookshop in the world - Foyles".
Indeed, on Thursday, despite a packed schedule of a luncheon with businessmen and talks at 10 Downing Street with his counterpart David Cameron, he squeezed in a visit to the British Museum to catch a special Vikings exhibition. As he said in his Facebook post: "All in all, a very good day."
Yesterday was another packed day as he toured London on a Routemaster, a bus with a "hop-on, hop-off" rear open platform. It is owned by Metroline, a ComfortDelgro subsidiary. During the ride, he quizzed Metroline chief executive Jaspal Singh on the revenue model and the fleet.
The former Singapore government official said Metroline has thrived partly because of certainty in the regulatory framework where operators are paid to run routes while the regulator collects fares. "We work closely with the regulator and there is trust, mutual respect and fairness," he said.
After the bus tour, Mr Lee had a dialogue at think-tank Chatham House, and opened Temasek Holdings' European office in London.