The French rugby team was boosted by performance-enhancing drugs during the 1980s according to a new book, most famously in their ferocious 1986 defeat of the All Blacks in Nantes.

The book written by investigative journalist Pierre Ballester alleges the French players were “loaded” on stimulants when they ran onto La Beaujoire Stadium in Nantes, before inflicting a 16-3 defeat on New Zealand.

The All Blacks had won the first Test 19-7 in Toulouse a week earlier.

Ballester quotes French team doctor at the time, Jacques Mombet, as saying the French use of amphetamines was most glaring in the game which became known as the “Battle of Nantes”.

“They each had their little pill in front of their plates for the meal before the match,” Mombet is quoted as saying in the book.

“The Blacks realised that their opponents, unrecognisable from the previous week, were loaded.”

All Blacks No.8 Wayne Shelford suffered a torn scrotum, lost several teeth and was knocked out cold during the Test.

Years later he voiced his suspicion about the French improvement in the space of a week.

“I always believed they were high on uppers or something during that Test,” Shelford said.

“I don’t think any team can come out to play like that after being beaten the way they were the week before.

“When they left their room you could see their eyes were all glazed. It was a brutal match.”

Mombet said the New Zealand Rugby Union had made a complaint to the International Rugby Board following the Test.

He said the IRB’s subsequent approach to the French sports ministry triggered a clampdown on drug use in France.

Former French players have previously said drug-taking was rife in the 1980s, comparing it to cycling.

Former France coach Bernard Laporte told a French parliament hearing in 2013 that players took drugs without knowing they were banned.

Ballester’s book “Rugby a Charges, l’enquete choc” (The case against rugby) also hints at the use of supplements by some current players.

France’s rugby establishment has not commented on allegations in the book, which is due for release next week.