The Hubble Constant from (CLASS) gravitational lenses

One of the main objectives of the Cosmic Lens All-Sky Survey (CLASS) collab oration has been to find gravitational lens (GL) systems at radio wavelengt hs that are suitable for the determination of time delays between image pai rs. The survey is now near completion and at least 18 GL systems have been found. Here, I will discuss our efforts to measure time delays from several of these systems with the ultimate aim of constraining the Hubble Constant (H-0). Thus far three CLASS GL systems (B0218+35.7, B1600+434 and B1608+65 6) have yielded measurements of time delays, from which values of Ho 60-70 km s(-1) Mpc(-1) have been estimated. Although most GL systems give similar values of H-0, statistical and systematic uncertainties are still consider able. To reduce these uncertainties, I will mention two monitoring programs that we are undertaking to (re)measure time delays in 14 CLASS GL systems and address several important issues for the near future.