In June 2018 Yorkshire Tea (part of Taylors of Harrogate) became the first major UK tea brand to publish its supplier list. The brand made the move following the "Who picked my tea?" campaign by Tradcraft Exchange. In August 2018, Twinings followed suit and published its full list of tea suppliers. In November 2018, Tetley (part of Tata Global Beverages) became the third British tea company to release a list of its suppliers. Clipper followed suit shortly after, making it the fourth British tea brand to do so. In January 2019, Unilever shared details of suppliers for all its British tea brands, including market leader PG Tips, and in September 2019 revealed its global tea suppliers. In April 2019, Typhoo pledged to release a list of its suppliers.

"Who picked my tea?" challenges the major tea brands to do more to tackle the poverty wages and poor conditions faced by workers on the tea estates in Assam. The campaign asks the six major brands, which together have 67% of the retail market, to publish which tea estates they are buying from in order to build transparency as a first step to bringing accountability for the working conditions.  

The six brands are: Yorkshire Tea (part of Taylors of Harrogate), Tetley (part of Tata Tea), PG Tips (part of Unilever), Typhoo, Twinings (part of Associated British Foods) and Clipper. 

On 5 March 2019, Marks & Spencer became the first British supermarket to publish details of its tea suppliers in response to the campaign. Traidcraft Exchange, the charity behind the campaign, is calling on other supermarkets to follow suit, particularly given the impact of their lower prices on the industry.