The work of the Cambridge group on QCD at LEP1 continued into the LEP2 era. Special interest was attached to the evolution of QCD predictions with energy, which is precisely predicted by the theory. By comparing the data at LEP1 and LEP2, recorded with the same detector, we expect to test these features of QCD with minimal systematic uncertainties. In particular, we are studying the event shape observables which are sensitive to the value of the strong coupling strength, αs. For example, we show below the energy dependence of this coupling strength, which is seen to fall with energy as predicted by QCD.
