Government agencies are still buying peat-based compost even though the environment secretary is planning to ban it, new data has revealed.

Peatlands occupy about 12% of the UK’s land area, and are the country’s largest natural carbon dioxide store, locking in an estimated 3.2bn tonnes of CO2, as well as providing habitats for birds, insects and plants. For years they have been neglected and dug up, and currently just 20% of UK peatlands remain in a natural state.

This autumn has also seen five times more fires than usual on English peat moorlands, as part of the grouse-shooting industry’s practice of stripping back heather, figures compiled by Wild Moors and Unearthed revealed last week.

Earlier this year, to the relief of campaigners, the environment secretary, George Eustice, finally announced plans for a ban on the sale of peat-based compost, sourced from peatlands.

But data obtained through freedom of information laws shows that agencies overseen by the Department for Environment, Food and Rural Affairs (Defra) have bought thousands of cubic metres of peat-based compost over the last five years, and have no plans to put an end to its use.

Conservation groups have described the continued use of peat-based compost by the public sector as “unacceptable,” saying it “flies in the face of the government’s legal commitments to tackle the climate and nature emergencies”.

The newly released data shows that Forestry England, Forest Research, and the Lake District National Park Authority have between them bought 3,833 cubic metres of peat-based compost over the last five years. All three government bodies are ultimately overseen by the environment secretary, who earlier this year highlighted the importance of peatlands as the UK’s “biggest terrestrial carbon store and home to some of our rarest species”.

Asked whether there was a target date by which they aimed to phase out the use of peat-based compost, the Lake District National Park Authority said it had “a plan to not purchase peat compost from 1 April 2022”, and pointed out that it had not bought any since 2019-20.

However, neither of the other bodies provided such a date. Forestry England said: “We have tried 100% peat-free products but so far these have not been successful. We will continue to work with suppliers to find more effective products and we look forward to the government’s England Peat Strategy.”

Forest Research – which has bought nearly 12,000 litres of peat-based compost in 2021 so far – said: “We are in the process of investigating alternative growing media for use in our intensive nurseries that fully meet our specific requirements, in accordance with current government procurement guidance.”

The FoI responses also revealed that Defra agencies are sourcing their peat from suppliers who carry out peat extraction at sites within the UK. This means it is possible that the government is buying compost made from peat mined from British sites, despite having itself warned that this causes damage in terms of both habitat loss and increased carbon emissions.

Among the suppliers used by Defra agencies are ICL, a multinational chemicals company, and Westland Horticulture, which produces compost sold by a range of household names.

ICL carries out peat extraction at three sites in Dumfries and Galloway and South Lanarkshire, using the peat to produce “growing media” or compost. It has recently run into significant local opposition to its proposals to extend extraction operations at the sites years further into the future.

Westland Horticulture mines peat at a site in Midlothian, and in 2017 was granted permission by the council to continue operations until the 2040s, despite strong criticism from conservation charities.

The sites at which both Westland and ICL carry out peat extraction are just 30 to 60 miles from Glasgow, where the UK government will host a major UN climate change summit next month.

ICL was contacted for comment. Westland told the Guardian that it has put together a roadmap to reduce its peat use and is “now using over 80% of non-peat materials across its operation, significantly ahead of the wider growing media industry. In order to deliver this significant and sector leading change Westland has invested over GBP50m in R&D through to manufacturing of proprietary peat free alternatives.”

Green groups and scientists have criticised the government for its continued use of peat-based compost.

Jenny Hawley, the policy manager at the conservation charity Plantlife, said: “The continued use of peat by the government’s own agencies and local authorities is unacceptable. Back in 2010, the UK government committed to phase out public procurement of peat by 2015 and amateur peat use by 2020. Almost seven years on, it’s incredibly frustrating that both targets have been missed and so little progress has been made.”

Dr Janet Moxley, a soil scientist who co-authored a report on emissions from peatlands for the UK government, said: “Both Forestry England and the Lakeland District National Park have funded peatland restoration projects, while at the same time purchasing peat products. Given that UK government procurement policies have contained guidance against purchasing peat products for some time, it is unfortunate that these organisations continue to use peat as a growing medium.”

A spokesperson for Defra said: “We have always been clear of the need to end the use of peat in horticulture in England, and we urge all gardeners to play their part and only use peat-free products.

“While there has been some progress, with industry monitoring revealing a 25% decrease in peat sold from 2011 to 2019, in the England Peat Action Plan we have committed to publishing a full consultation in 2021 on banning the sale of peat and peat containing products in the amateur sector by the end of this parliament.”

Mike Seddon, Forestry England’s chief executive, said: “Although we have already reduced the proportion of peat we use from 80% to 65% several years ago, we will keep pushing. The 100% peat-free products we have trialled so far did not provide a sufficiently high production rate of successful forest transplants. We will keep collaborating with suppliers and testing alternatives.”