Chicago, Hammersmith Apollo, London

Like the Beach Boys, with whom they have often toured and occasionally recorded, Chicago make some of the sunniest, beaming smile-happiest music ever. They also both exemplify what the US music industry can do to its brightest sparks as commercial considerations take over and suck the life out of a group.

Once a cutting-edge, underground, jazz-rock outfit, as they remind the audience by opening with the ambitious "Ballet for a Girl in Buchannon", the complex suite from the second of the three extraordinary, groundbreaking double albums they released within 20 months at the start of their storied 40 year-career, they became soft rockers ordinaires with "If You Leave Me Now".

Dispatched less than halfway through a two-hour-plus concert that offered value for money and a notable improvement on their previous return to British shores three years ago, the 1976 chart-topping smoochie wasn't exactly a stylistic departure for the band, since "Ballet" includes the gorgeous "Colour My World", then the B-side of their first US Top 10, "Make Me Smile", and now a prom-night slow-dance favourite.

Still guided by the impossibly handsome pianist Robert Lamm, whose affecting voice shone on "Does Anybody Really Know What Time It Is?", the trombone-player James Pankow and the trumpeter Lee Loughnane, assisted by six musicians who have joined along the way, most notably bassist and singer Jason Scheff, Chicago have always dealt with matters of the heart, even if they fell into the generic power balladry of "Along Comes a Woman". The bright, upbeat "(I've Been) Searchin' So Long" and "Saturday in the Park" were redolent of happier times when the can-do US was at ease with itself.

However, the group really excelled when they charged towards the front rows will all horns blaring, as for the mighty "Beginnings" or an impressively dynamic and hypnotic finale to the mid-Eighties biggie "Hard Habit to Break", or when they essayed the Latin-infused funk of the much-sampled "Street Player". The encore of early favourites "Free" and "25 or 6 to 4" rather suggested the band could structure future concert appearances around specific periods if not albums, to better satisfy their dedicated following. Chicago's early incarnation always seemed to be on a quest and a Journey-style revival and reappraisal of its rich catalogue is overdue.