 The head puppet sculptor was Christine Glanville , who also served as the lead puppeteer . Glanville 's four @-@ person team built the 13 members of the main cast in six months at a cost of between £ 250 and £ 300 per puppet ( approximately £ 4 @,@ <unk> and £ 5 @,@ 483 today ) . Since pairs of episodes were being filmed simultaneously on separate stages , the characters needed to be sculpted in duplicate . <unk> expressions were diversified by means of <unk> heads : as well as a head with a neutral expression , each main character was given a " <unk> " , a " <unk> " and a " <unk> " . The finished puppets were approximately 22 inches ( 56 cm ) tall , or 1 ⁄ 3 adult human height . 
