The Spice Girls are “deeply shocked and appalled” after it emerged workers in India making their T-shirts for Comic Relief were allegedly grossly underpaid.

Geri Horner, Melanie Chisholm, Emma Bunton, and Melanie Brown have reformed the '90s girl band for a reunion tour. Fellow original member Victoria Beckham decided against rejoining her bandmates.

And according to editors at The Guardian, T-shirts with the message ‘#IWannaBeASpiceGirl’ on the front and ‘gender justice’ on the back were made at a factory in Bangladesh by employees working 16-hour shifts.

The $24.92 (£19.40) T-shirts were commissioned and designed by the band with $14.60 (£11.60) earmarked to be donated to Comic Relief’s fund to help “champion equality for women”.

However, one employee of Interstoff Apparels told The Guardian: “We work in inhuman conditions.”

Other allegations made by the mainly female workforce include managers using abusive language, and machinists claiming they were forced to work up to 16 hours a day, reported the publication.

"The band are grateful that this information has been brought to their attention," it said in a statement. “As to be expected, they are deeply shocked and appalled by these claims and have demanded a full explanation from Represent - the company they employed to handle this."

The Spice Girls have now asked that Represent donate their profits to local charities in Bangladesh.

Comic Relief added it was “shocked and concerned by the allegations”. According to the organisation, Represent switched to a different supplier, Belgian company Stanley/Stella, after initial sourcing checks has been made.

The new supplier reportedly used the factory where the alleged mistreatment took place, without informing the Spice Girls or Comic Relief.

Represent told The Guardian the allegations were “appalling and unacceptable” and that it planned to refund customers. The company said it took “full responsibility” for its choice of Stanley/Stella "due to the brand’s strong reputation and leadership within the Fair Wear Foundation”.

Interstoff Apparels' director Naimul Bashar Chowdhury has insisted the allegations are “simply not true”.