Although once a member of the Labour Party, he became a typical dogged Liberal Democrat activist who through sheer hard work and attention to individual and community problems got himself elected to the council.
In an overwhelmingly Labour area, he won his seat in South ward in 1987 and held on twice, the last time in May. But his majority was just 73 votes and he emerged as the only non-Labour member of the 60-strong council in north-east London.
He was accorded a generous tribute by the Newham Recorder, the local newspaper. In a leading article, it said: 'His election in the face of sweeping socialist gains is a tribute to the work he has done and to his personal style of putting people's interests above scoring political points.'
The Liberal Democrats may now feel that Mr Kellaway, who has fought local constituencies for them in the last three general elections, has scored a humiliating litical point. Kathleen King, chairwoman of the local party, said: 'I'm upset and disappointed. We could have got as many as 12,000 votes, but he's prevented that. The really sad thing is that our supporters now have nowhere to go and I blame him for that. The timing was the most annoying thing of all.'
Even before his extraordinary announcement yesterday it was clear that Mr Kellaway, 40, a self- employed economist and market research consultant, enjoyed cordial relations with his Labour opponents on the council.
The majority party allowed him to join council delegations and Mr Kellaway said: 'They don't ignore me, they include me.' His Labour opponent in the by-election, the former council leader Stephen Timms, was extremely generous about his qualities. But despite the amicable relations, Mr Kellaway seemed quite definite about his loyalties. Just two weeks ago, he said he preferred the Liberal Democrats because it was a 'more open and democratic party'.
Mr Kellaway, who has lived in Newham all his life, seemed well cast as a lone, slightly eccentric, battler. He once worked for the Henley Centre, which specialises in forecasting, but even their experts could not have predicted this switch of political loyalties.