Production Number: Unknown


Scientists Thornton and Carter continue in private the research into accelerated plant growth that they had begun together at the Ministry of Agriculture. Thornton has left the Ministry and requires Carter, still working there, to steal radioactive chemicals for their research. They soon make a breakthrough and successfully grow a tomato plant to much greater than normal size. However, a careless accident in which some of the concentrated radioactive solution is washed down the sink and into the sewers, the scientists' problems begin to grow – literally.

Steed, Purdey and Gambit hear reports of large movements and disappearances in the sewers under central London. Steed stays at home to postulate on theories and arrive at a solution, while Purdey and Gambit leave to patrol the dark and grimy sewers of the capital city. While they are there, they discover agents of a foreign power at large and a series of gruesome killings take place. It quickly becomes apparent to Steed that the killer is not a man, but a genetically mutated sewer rat which has grown to an enormous size. In the tunnels, Purdey is tracking Thornton, unware that something bigger, hairier and hungrier is tracking her! 

The New Avengers: Series 1, Episode 12
Production Completed:
Oct 1976
Recording Format: 35mm Colour Film
Archive Holding: 35mm Colour Film


Anglia: Tue 21 Dec 1976, 8.00pm
ATV Midlands: Fri 28 Jan 1977, 7.30pm
Border: Currently unconfirmed
Channel: Currently unconfirmed
Grampian: Currently unconfirmed
Granada: Fri 28 Jan 1977, 7.30pm
HTV: Sun 13 Mar 1977, 7.25pm
Scottish: Currently unconfirmed
Southern: Fri 28 Jan 1977, 7.30pm
Thames: Tue 21 Dec 1976, 8.00pm
Tyne Tees: Currently unconfirmed
Ulster: Fri 28 Jan 1977, 7.30pm
Westward: Fri 28 Jan 1977, 7.30pm
Yorkshire: Wed 2 Mar 1977, 8.00pm
AUSTRALIA: Wed 20 Apr 1977
Thu 10 Mar 1977
Thu 25 Sep 1980
Sat 26 Feb 1977
GREECE: Fri 8 Jul 1977
IRELAND: Tue 14 Dec 1976
ITALY: Thu 17 Aug 1978
MALAYSIA: Thu 26 Jan 1978
NETHERLANDS: Thu 23 Dec 1976
SINGAPORE: Wed 27 Jul 1977
SPAIN: Sun 19 Jul 1981
SWITZERLAND: Tue 26 Apr 1977
TURKEY: Sun 6 Dec 1981
UNITED KINGDOM: Tue 21 Dec 1976
USA: Fri 29 Dec 1978
WEST GERMANY: Mon 5 Mar 1984
John Steed
Mike Gambit
Charles Thornton
George Ratcliffe
Tramp Joe
Tramp Arthur
Edward Harlow
Patrick Malloy
Patrick Macnee
Gareth Hunt
Joanna Lumley
Julian Holloway
Peter Cellier
Jeremy Young
Patrick Malahide
Keith Marsh
Ken Wynne
Morgan Shepherd
John Watts
Keith Alexander
Ronnie Laughlin

Not released.


No episode-specific DVD extras available.


Writer – Dennis Spooner
Series Theme & Music –
Laurie Johnson
Production Designer –
Syd Cain
Director of Photography –
Mike Reed B.S.C.
Producers – Albert Fennell and Brian Clemens
Director –
Ray Austin

Editor – Bob Dearberg
Assistant Director – Ron Purdie
Location Manager – Nicholas Gillott

Camera Operator –
Herbert Smith
Sound Recordists –
Danny Daniel, Ken Barker

Dubbing Editor –
Peter Lennard, Mike Hopkins
Casting Director –
Maggie Cartier
Art Director –
Robert Bell
Set Dresser – Simon Wakefield

Hairdressing Supervisor – Helene Bevan
Make-up – Alan Boyle, Alan Brownie
Wardrobe Supervisor – Jackie Cummins
Fight Arranger – Cyd Child
Continuity – Renιe Glynne
Post-Production Co-ordinator –
Paul Clay
Production Supervisor – Ron Fry
Unit Manager – Robert Fennell
Construction Manager – Leon Davis

Processed by Rank Film Laboratories

Made at Pinewood Studios and on location

A Production of The Avengers (Film & TV) Enterprises Ltd
for TV Productions and I.D.T.V. Paris


An episode I hold in considerable affection, but one that truly divides Avengers fandom. The script is no great shakes, with its scenario firmly rooted in 1950s B-movie horror, but this is an episode that wouldn't have been out of place in the colour era of the original series. The wry twist on the title of a certain shark-centred horror film appeals to my sense of humour, too – although it is something of a relief that Laurie Johnson resisted delivering a pastiche of John Williams famous score for Jaws. The absence of Patrick Macnee from the majority of the episode is certainly a weakness, but the day is saved by taut, claustrophobic direction from Ray Austin that owes much to Hitchcock's influence. Even the potentially embarrassing reveal of the giant rat at the end is far better than you expect. A guilty pleasure perhaps, but a pleasure nonetheless.


  • Production Brief... Patrick Macnee's screentime in this episode is astoundingly brief – John Steed is away from the main action for the vast majority of Gnaws, and his character is barely referred to. Macnee was unhappy with his diminished role in many first series episodes of The New Avengers, and this was addressed for the second.

  • Joanna Lumley later revealed that she refused to be terrified of the monstrous sewer creature, as she was in fact rather fond of it!

  • On Location... Unusually for The New Avengers, Gnaws is practically studio-bound, with only two short sequences shot on location. Both of these were filmed in the grounds of Pinewood's Heathenden Hall. All the sewer sequences were filmed on stages at Pinewood, so it wasn't quite as distasteful an assignment for The New Avengers as it might at first have appeared.

  • Trivia... Purdey is briefly seen to model a complete Burberry ensemble. Burberry is a British tartan-based fashion range with a long history dating back to 1856.

  • The headstone of Harlow's grave does not specify a date of birth or death. It merely says, 'Edward Harlow R.I.P.'.

  • Before the mysterious killer roaming the sewers is revealed to be a giant rat, witnesses believe it to be a shark and then a snake. Steed cooly explains how this was possible using a handy illustration and cut-out masking frame. He should have been on Blue Peter...

  • Throughout the episode, much is made of the tomato plant that Thornton is experimenting upon and which is growing at a rapid rate. By the end of the episode, it is about the size of a football and Purdey serves it up to her Avenger friends as part of a tomato salad. Considering that everything else that has come into contact with the growth chemical is radioactive... it's debatable whether this was a particularly good idea!

  • Bloopers... Continuing on the radioactivity theme, the radioactive chemicals that Carter steals from the safe are stored in a yellow cashbox. The back of the safe has been corroded by radioactivity, and yet when Carter and Thornton handle the tin and the syringes within they do so without any protection or precautions... Maybe not a blooper per se, but somewhat naive for scientists at the very least!

  • And Finally... Thornton's laboratory, for no adequately explained reason, has direct access to the sewers beneath it. This is wonderfully convenient for mad scientists who carelessly spill radioactive growth chemicals down there and then have to descend to hunt the giant creatures that they have inadvertently mutated... No research laboratory should be without it...

Plotline by Alan Hayes • UK Transmissions by Simon Coward and Alan Hayes
International Premieres by Denis Kirsanov • Ministry Verdict by Alan Hayes
Declassified by Gareth Humphreys and Alan Hayes


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