Press Association photograph titled 'TV at the Scrubs'. Caption on back reads: Television cameras are in position today (Monday) on the forbidding outer walls of Wormwood Scrubs, but authorities at the London prison hope there'll be no thrillers in which escaping prisoners play the leading role. The cameras, which can scan both sides of the perimeter wall, have been placed in position as a precaution against jailbreaks. Other precautions include arc lights, observation towers at vantage poinhts, and concrete posts at the outisde foot of the walls to prevend parking of vehicles which might be used in an escape bid.