By this time Barker had achieved a central position in the booming economic history. After a year in exile at Aberdeen, he was chosen to join T.S. Ashton’s staff at the London School of Economics in 1953, and he became Secretary of the Economic History Society in 1960 He became widely known for his bustling energy. No one was surprised when in 1964 he was chosen to be one of the founding professors at the new University of Kent.In Canterbury, he was happy planning new courses, colleges, wine committee tastings, and he continued to create the new social history of the 1960s by lecturing with enthusiasm about, for example, the social role of spectacles, and the economic impact of the rise of false teeth He loved those heady days.

Nineteen seventy-six saw Barker tempted back to LSE as Professor of Economic History in succession to the very clever but difficult F.J. Fisher; it was also the year in which the Economic History Society celebrated its jubilee and the year in which its membership boom came to a clear end. Barker remained at LSE until he took early retirement in 1983. He did not like decline.Besides the two major works already cited, Barker in 1963 produced his outstandingly good A History of London Transport, making buses and the Underground in the 19th century seriously interesting, the first of a two-part work completed by Michael Robbins a few years later with his companion volume on the 20th century. Subsequently there were re-workings of these three important works in various ways, as well as well-turned-out histories of City livery companies, the Girdlers, the Carpenters, the Pewterers, the latter two in partnership with former students, Bernard Alford and John Hatcher, both later distinguished professors of economic history at Bristol and Cambridge respectively.Theo Barker liked enjoying himself, and so did his wife Joy, the opera singer and teacher Judith Pierce. He had a warning heart attack in the early 1980s, but he decided, lacking dependents, to continue to enjoy himself to the full.

He gave in Who’s Who, for example, among his recreations “visiting parts of Europe which many others do not reach” He had two clear principles of continental travel One was never to drive more than 200 miles a day. The other was each evening to buy a case of a carefully chosen local wine to bring back.Once I met him in Vienna His car contained six cases of wine, plus a lot of luggage. Joy and Theo, larger than life as ever, appeared quite oblivious that their car was putting such pressure on its suspension that there was very little clearance above the Autobahnen And they were driving on to a conference in Budapest .Barker loved food and wine. He could be difficult to invite to dinner, since he would turn up with a bulging bagful of opened bottles he wanted everyone to taste and discuss, regardless of the perhaps carefully planned choices of the host.

At a conference in Edinburgh he appeared in the Staff Club when I was having a drink with a friend who had chosen Glenmorangie: “You can’t drink that”, said Theo revealingly, “Everybody has heard of that.”Barker’s students were devoted to him, but not all his colleagues were. “We must get someone to work on this” was a characteristic cry, with all sorts of suggested research topics bubbling up. “If you think it’s so important, why don’t you work on it yourself?” one of his colleagues at LSE witheringly said on one occasion. Some found him over-enthusiastic, Panglossian and self-satisfied. This was the view that narrowly prevailed in the British Academy, and Barker was bitterly disappointed at never being elected a Fellow.Even his Presidency of the International Historical Congress in the early 1990s, as well as his many other bustling official activities, did not earn him recognition by the state, as should have been the case.