A programme of visible multi-colour monitoring of blazars was started in th
e Canary Islands in 1986. Infrared monitoring was added to the programme in
1988. The sample of objects to be observed is deliberately kept small to e
nsure that each one receives an acceptable level of light curve coverage. T
he programme was carried out using scheduled telescope time and a small amo
unt of service observations. We describe the aims of the monitoring program
me and show some of the results obtained. (C) 1999 Elsevier Science B.V. Al
l rights reserved.