Major high street names including Primark, Boohoo and Missguided have come under fire for fuelling a throwaway fast fashion culture that has been linked to the exploitation of low-paid workers in UK factories.

Britons buy more new clothes than any other country in Europe and MPs are looking at the environmental and human cost of £2 and £200 T-shirts amid growing concerns the multibillion-pound fashion industry is wasting valuable resources and contributing to climate change.

The low prices in Primark stores, where T-shirts can cost as little as £2, were challenged by MPs on the Commons environmental audit select committee, who suggested shoppers viewed its clothing as disposable.

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“Isn’t the real problem with the fast fashion industry that if you are selling stuff at £5 people aren’t going to treat it with any respect and at the end of its life it’s going to go in the bin?” asked the Labour MP Mary Creagh, the committee chair.

Paul Lister, Primark’s head of ethical trade and environmental sustainability, denied that was the case: “We are proud of the quality and durability of our garments. They are not bought to throw away.”

Lister said the retailer kept its prices low by shunning traditional advertising, which saved it about £150m compared with rivals and “that goes straight into price”. He said he knew of no one under 16 working in any of its supply factories.

“Factory to store, we keep our costs to the absolute minimum and in store we keep margins very tight,” he said. “Our business model takes us to a £2 T-shirt.”

While Primark was forced to defend its low prices, Burberry was scrutinised over its now-defunct policy of burning piles of unsold expensive clothes.

Leanne Wood, the brand’s chief people and corporate affairs officer, told MPs it was an industry-wide practice: “We’re the only luxury business that’s reported it in their accounts … but it is something that happens in the industry.”

Online retailers Asos, Boohoo and Missguided were questioned about the health checks carried out on the large number of Leicester factories they worked with.

An investigation by Channel 4’s Dispatches alleged last year UK factories supplying retailers such as River Island, New Look, Boohoo and Missguided were paying workers between £3 and £3.50 an hour. A Financial Times investigation (£) also found examples of exploitation in Leicester factories.

Creagh questioned how it was physically possible for Manchester-based Boohoo to sell UK-made dresses for £5 when the hourly minimum wage was £7.83.

The company’s joint chief executive Carol Kane said the company did not make any profit on the £5 dresses, which were “loss leaders” designed to attract shoppers to its website. The typically short dresses, made out of polyester and elastane, featured no zips or buttons, so were easy for machinists to run up, she said.

“We do not make a profit on a £5 dress,” said Kane, adding that the cost price of the garments was even less at £2.50 to £3. “It’s a loss leader. It’s a marketing tool designed to drive visitors to the website.”

Asos and Missguided told the hearing they had pulled production from a number of factories in Leicester that fell short of their standards.

The select committee is examining the impact of clothing production, ranging from environmental cost to worker conditions, especially when garments are produced cheaply and quickly in response to fast fashion trends.

With 300,000 tonnes of clothing sent to landfill every year in the UK, Primark said it would launch a clothing collection service in all its stores next year in a similar vein to Marks & Spencer’s “shwopping” scheme.

But Mike Barry, M&S’s head of sustainable business, said collecting unwanted clothes was not the biggest problem for the industry – it has collected 30m garments over the past decade – but what to to with them, given the lack of a domestic industry to process the material. “It is quite possible to prevent clothing going to landfill but much harder to do something with the fibres you recover.”

The environmental cost of UK fashion

Britons spend £52.7bn a year on fashion, according to the government-backed Waste and Resources Action Programme (Wrap). The lion’s share (£47.4bn) goes on clothing while £4.5bn is spent on accessories.

The amount of clothes bought each year continues to rise – 1.13m tonnes in 2016, up from 950,000 tonnes in 2012, according to a 2017 Wrap report.

The total carbon footprint of the clothing worn in the UK was 26.2m tonnes of CO2e in 2016, up 9% on 2012. The carbon footprint per tonne fell 8% but was outweighed by the increase in consumption.

About 1m tonnes of clothing is cleared out of wardrobes every year. Of that, 700,000 tonnes is collected for reuse and recycling with the remainder sent to landfill or incinerated, at an estimated cost of £82m.

In the UK, two-thirds of clothing is made from synthetic plastic materials, which are among the leading contributors to microplastic pollution. Up to 2,900 tonnes of microplastics from the washing of synthetic clothing such as fleeces could be passing through wastewater treatment into UK rivers and estuaries, according to a recent Friends of the Earth report.