In  1976  the  BBC  started  its  own  live marathon­-length Saturday morning children's show, The Multi Coloured Swap Shop and, seemingly to counteract the impact  of  this move, some other ITV regions (Anglia serving east England, Granada serving Lancashire, HTV serving Wales and the west, Southern TV, and Scottish Television serving Central Scotland) also started carrying Ttswas. By this time John Asher had left the team and Sally James had joined. This last move served to attract even more older audience members, especially adolescent boys and their fathers, who took a shine to James and her "rock chick" appeal. The presenters continued to deal out doses of slime and buckets of water, but the slop value of the show was increased considerably the following year ( 1977) with the introduction of the Phantom Flan Flinger, a masked custard-pie throwing and water-slinging mystery man who would be responsible for drenching many of the celebrity guests who appeared on the show.

     The series went from strength to strength and further consolidated in 1979, when it was also transmitted in the Grampian (North East Scotland), LWT (London), Westward (South West England), and Yorkshire Television regions, virtually covering the land. This was to be the show's most popular period, with a winning team of varying personnel including, alongside Tarrant and James, larger-than-life impressionist Lenny Henry; comedian (later Dr. Who star) Sylvester Mc­ Coy; former pop singer John Gorman; veteran Irish comic Frank Carson, and the dry-witted Bob Carol­ gees whose puppet, punk dog Spit, became a firm favorite with audience members and home viewers. By this time celebrities were lining up to be on the show.

     Victims included Paul McCartney. Genesis. Cliff Richard. Kate Bush. The Clash. and senior newscaster Trevor McDonald-mercilessly  soaked  while  reading a spoof news item. Other recurring favorite moments of the show were: The Cage. in which adult audience members were imprisoned and regularly soaked by having buckets of water thrown over them; Compost Corner. a pastiche gardening segment also ending up with someone getting wet; the Dying Fly. in which the audience members were encouraged to lie on their back and wiggle their legs and arms in the air; the pop interview. which would start normally enough but was prone to end in chaos; and the small children talent slot. during which young audience members were given the chance to show off their (often excruciating) party pieces.

     By the end of  the 1979 season  the show had become so popular that the central team (Tarrant, James, Gor­man and Carolgees) had toured as The Four Bucke­teers. soaking audiences up and down the country and releasing a minor hit single (""The Bucket of Water Song"). The adult appeal of Tiswas had grown considerably; this was reflected occasionally by the (often unintentionally) risque nature of some of the items. It proved impossible to resist this older appeal and Tar­ rant. Gorman and Carolgees left in 1981 to produce and present OTT (Over The Top) from 1982. a late­ night adult version of Tiswas. However, the intentionally rude and crude nature of the new show failed to spark interest or engender the sort of cult appeal that had turned Tiswas into a phenomenon. Tiswas itself continued unabashedly at first, but soon after showed signs of wear and tear, and ended in April 1982. The series had revolutionized U.K. children's broadcasting. paving the way for a saucier, livelier approach to the field and demonstrating to no little extent the appeal of slapstick comedy. pop music. and silliness to both the young and the young at heart.