 After viewing the completed 25 @-@ minute pilot , " Trapped in the Sky " , Lew Grade was so impressed by APF 's work that he instructed Anderson to double the episode length and increased the series ' budget per episode from £ 25 @,@ 000 to £ 38 @,@ 000 . As a result , Thunderbirds became not only the company 's longest and highest @-@ budgeted production , but also among the most expensive TV series to have been made up to that point . The crew , who had been filming at a rate of two 25 @-@ minute episodes per fortnight , faced significant challenges during the transition to the new format : eight episodes had already been completed , scripts for up to ten more had been written , and substantial rewrites would be necessary to satisfy the longer running time . Anderson lamented : " Our time @-@ scale was far too drawn out . ITC 's New York office insisted that they should have one show a fortnight ... Everything had to move at twice the speed . " APF spent over seven months extending the existing episodes . 
 After viewing the completed 25 @-@ minute pilot , " Trapped in the Sky " , Lew Grade was so impressed by APF <a href='null_genetive' title='1'><mark>'s</mark></a>work that he instructed Anderson to double the episode length and increased the series <a href='null_genetive' title='2'><mark>'</mark></a>budget per episode from £ 25 @,@ 000 to £ 38 @,@ 000 . As a result , Thunderbirds became not only the company <a href='null_genetive' title='3'><mark>'s</mark></a>longest and highest @-@ budgeted production , but also among the most expensive TV series to <a href='been_done' title='4'><mark>have</mark></a> been made up to that point . The crew , <a href='null_relcl' title='5'><mark>who</mark></a>had been filming at a rate of two 25 @-@ minute episodes per fortnight , faced significant challenges during the transition to the new format : eight episodes <a href='been_done' title='6'><mark>had</mark></a> already been completed , scripts for up to ten more <a href='been_done' title='7'><mark>had</mark></a> been written , and substantial rewrites would be necessary to satisfy the longer running time . Anderson lamented : " Our time @-@ scale<a href='been_done' title='8'><mark></mark></a> was far too drawn out . ITC <a href='null_genetive' title='9'><mark>'s</mark></a>New York office insisted that they should have one show a fortnight ... Everything had to move at twice the speed . " APF spent over seven months extending the existing episodes . 
After viewing da completed 25 @-@ minute pilot , " Trapped in tdaSky " , Lew Grade was soo impressed by APF  wrk dat he instructed Anderson to double the episode length and increased the series  budget per episode from £ 25 @,@ 000 to £ 38 @,@ 000 . As a result , Thunderbirds became not only the company  longest and highest @-@ budgeted production , but also among thdaost expensive TV series to done been made up to that point . Thedaew , had been filming at a rate of two 25 @-@ minute episodes per fortnight , faced significant challenges durin the transition to the da format : eight episodes done already been completed , scripts fa up to ten more done been written , and substantial rewrites would be necessary to satisfy the longer runnin time . Anderson lamented : " Our time @-@ scale done was far too drawn out . ITC  New York office insisted that they should have one show a fortnight ... Everything had to move at twice the speed . " APF spent over seven months extending the existing episodes .