All purchasers of the shirts will be reimbursed.
The Spice Girls have released a statement declaring that the band is “deeply shocked and appalled” by investigative reports which found that its Comic Relief 'gender justice' T-shirts were made in a Bangladesh factory where women earn the equivalent of 35p an hour.
The charity shirts, which bear the message '#IWannaBeASpiceGirl' across the chest, were produced by mostly female machinists who told The Guardian that they were forced to work up to 16 hours a day and were verbally abused and harassed for not hitting targets.
Comic Relief is due to receive £11.60 from the sales of each £19.40 T-shirt for its Power Up initiative, which is part of its Gender Justice campaign but is yet to receive any money from the garments sold during a three-week period last year.
"The girls will personally fund an independent investigation into the working conditions of this factory," a spokesperson for The Spice Girls said.
"Equality and the movement of people power has always been at the heart of the band."
Comic Relief said the online retailer commissioned to make the T-shirts had switched suppliers without telling either it or the Spice Girls, away from an agreed supplier which had been ethically vetted.
A spokeswoman said: "Comic Relief is shocked and concerned by the allegations in The Guardian.
"No-one should have to work under the conditions described in the piece.
"To be very clear, both Comic Relief and the Spice Girls carried out ethical sourcing checks on the supplier Represent told us they would be using for production of the T-shirts."
Online retailer Represent said it was "deeply disturbed" by the allegations, which it described as "appalling and unacceptable".
"Represent has strict ethical sourcing standards for all of our manufacturers," the company said.
"Comic Relief and Spice Girls did everything in their power to ensure ethical sourcing."
Represent said it had chosen a supplier because it believed it had a reputation for upholding ethical standards.
The company said it took "full responsibility" for choosing the supplier, adding: "(We) confirm that this is something that we didn't bring to the attention of Spice Girls or Comic Relief.
"We will make refunds available on request to anyone who bought a shirt."
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