According to Wikipedia:
Lesney's response to this was relatively quick — but not quick enough to avoid major financial worries — creating the "Superfast" line. This was effectively a transformation of the 1969 line to include low-friction wheels (at first narrow, since the company needed time to retool the series to accommodate wide tyres), often accompanied with new colors. The result was, at first, a strange but interesting line of fast-wheeling cars, trucks, and trailers, basically complete in 1970. Racing track sets and the like were also released to allow children to race their cars. Starting in 1970 and particularly in 1971, new models appeared with wider tyres, and older models (including trucks still in the line) were retooled to fit slicks. The King Size range was similarly updated, including a division into Super Kings (mostly trucks, but also with mag wheels) and Speed Kings (cars). A short-lived series of rechargeable electric cars, called Scorpions, was released as well, to compete with similar products from Hot Wheels (Sizzlers) and Corgi (ElectroRockets).This helped Lesney reestablish itself in the market, as would the resulting advertising the company produced. Eventually, Matchbox was sold to Tyco Toys in 1993 and was subsequently purchased by Mattel in 1996.
'The Champions' followed the exploits of Matchbox Team Surtees, a tie-in with the sponsorship deal Matchbox had with Formula 2 contenders Surtees Racing Organisation, set up by racing driver John Surtees in 1970. One of his drivers, Mike Hailwood, won the 1972 European F2 Championship, the story of which is revealed through the following series of adverts.
My thanks to Richard Sheaf for sending over scans. We will have more episodes for you tomorrow.