The Government ignored expert advice and made changes in 2015 that made it easier to buy dangerous acids that have been used in a spate of attacks in recent weeks, The Independent can reveal.

Changes made in the Deregulation Act 2015 scrapped an obligation on sellers of dangerous substances, including acids, to be registered with their local council. The move was opposed by medical experts, who warned that it could make it easier for criminals to get their hands on highly toxic substances, and by the Government’s own advisory board on the regulation of hazardous chemicals.

Ministers boasted at the time about “cutting red tape” but are now under mounting pressure from MPs and campaigners to re-tighten laws to make it harder for people to get their hands on highly concentrated acids. It comes after dozens of people were injured in a spate of acid attacks, with London being particularly affected by the incidents.

Under previous legislation, namely the 1972 Poisons Act, any business selling dangerous substances was required to register annually with their local council, ensuring there was a record of companies selling hazardous chemicals. Those selling the most lethal chemicals also needed a licence from the Home Office.

However, the 2015 changes scrapped this requirement and now mean there is no longer any registration or licence needed to sell many dangerous chemicals. Only the most potent toxins, including those used to make explosives, are deemed “regulated substances” and require a licence to sell. Sulphuric acid and hydrochloric acid are included on a separate list of “reportable substances” that do not require a licence.

Instead of having to register with their local council, sellers of “reportable substances” are merely required to tell authorities about anyone buying a substance “if the supplier has reasonable grounds for believing the transaction to be suspicious”, such as if there is a suspicion the chemical is “intended for the illicit manufacture of explosives” or “any illicit use”.

The law says reasons for such suspicions could be if the customer is vague or uncertain about how they will use the substance, wants to buy large quantities, is unwilling to provide proof of ID or insists on “unusual methods of payment”.

If none of these take place, people are free to buy and sell powerful acids without any regulation, licensing or registration.

The changes made in 2015 were against the recommendations of the Poisons Board, a panel of experts established to advise ministers on regulating the trade in dangerous substances, who favoured tightening, rather than weakening, regulations so that high concentrations of acid could be sold only by licensed pharmacists.

However, ministers ignored the advice and used the Deregulation Act to completely abolish the Poisons Board.

Doctors were also opposed to relaxing regulations on the sale of poisons. In its response to the Home Office consultation on the proposals, the Royal College of Physicians of Edinburgh wrote: “The college disagrees with the proposals... Experts consulted by the college would prefer for at least the status quo to be maintained or more rigorous controls put in place.

“If the intention is to restrict the access [to highly toxic chemicals], then [the proposed change] does not work since they appear to be no longer controlled.

“The indicators of a suspicious transaction are subjective in some cases and require skill and experience to perform effectively. Pharmacists are well placed to do this as they are used to dealing with people attempting to obtain drugs inappropriately. It is not clear if other retailers could take on this responsibility effectively.”

Hundreds of mopeds block road outside Parliament in protest over acid attacks

At the time, Conservative ministers boasted about “cutting red tape for business” and claimed the change would save retailers £20,000 a year.

Oliver Letwin, the then Tory minister responsible for taking the changes through Parliament, claimed the system of making sellers of dangerous chemicals register with local councils was “an entirely purposeless exercise, which has gone on for years and years”. The changes to laws on dangerous substances were “considerable advances”, he said during a speech to MPs.

Campaigners told The Independent the deregulation could have made it easier for perpetrators to get their hands on the acids used in recent attacks.

Jaf Shah, executive director of Acid Survivors Trust International, said it was already clear that acid attacks were on the rise at the time the Government decided to relax laws on the sale of acids.

"I was becoming aware of an increase in acid attacks as early as 2013/14", he said.

"If tighter controls and legislation and stricter regulation had been introduced then there's a real possibility that some of the attacks may have been prevented. It may have acted as a sufficient deterrent for a number of would-be perpetrators.

"In light of the new, horrendous number of attacks being reported, the Government clearly needs to act pretty swiftly."

Mr Shah said that, if the Government had followed the Poisons Board's advice and tightened regulations rather than relaxing them, "it could have averted a number of attacks".

He called for immediate changes to re-introduce a licencing system, prevent cash purchases of acid because debit or credit card transactions are more traceable, and introduce an age restriction for purchasing acid.

Manufacturers should also make products less corrosive and thicker so they cannot be thrown or sprayed as easily, he said.

"Where there's a licencing system, it does seem to work. It will act as a deterrent to a number of young would-be perpetrators. If it was the case that the licencing system didn't work then you could argue there shouldn't be a licencing system for guns and knives.

"We need to see concentrated acids as a lethal weapon as we do guns and knives. A lot of the damage that's done in acid attacks carries lifelong repercussions because most survivors are targeted on their face, which leaves lifelong scarring and sometimes permanent disability in the form of blindness. The trauma lives with the survivor for many, many years. Most survivors say they can't shake it off because they have to face it every morning in the mirror."

The number of acid attacks in the UK has soared in recent months. Assaults involving the substance have more than doubled since 2012 and increased by 74 per cent in the past year alone, with the vast majority of incidents taking place in London.

Last year, there were 504 reports of acid attacks in the UK – up from 183 in 2012.

One suspect, named as Rahad Hussain, appeared in court yesterday over an acid attack in East London on Tuesday that left two men, aged 23 and 24, with "life-changing" injuries. The 23-year-old, who is from Tower Hamlets, has been charged with two counts of wounding with intent to do grievous bodily harm and one count of possession of an offensive weapon, namely acid. He was remanded in custody.

Earlier in July, five attacks were carried out in the space of 90 minutes in east London. One of the victims was left with “life changing injuries”.

Police say gang members are increasingly carrying substances such as acid instead of knives because the law is less strict on this type of weapon. It is illegal to carry a knife without a good reason, whereas carrying acid is not an offence unless it can be proved that it is to be used to commit a crime.

While it is impossible to link the rise in attacks to the change in law, ministers are likely to face questions as to why they removed the registration of sellers.

Five acid attacks carried out across London

They are now urgently looking at tightening the laws around acids to make it more difficult to sell, buy and carry the substances.

“We are working with the police to see what more we could do”, the Prime Minister’s spokesman said last week. A Home Office spokesperson also confirmed the department is “working on it”.

In the wake of the attacks, politicians including London Mayor Sadiq Khan called on the Government to tighten regulations and re-introduce a system similar in nature to the one that was in place before the 2015 reforms.

Labour MPs such as Stephen Timms and Lyn Brown have called for legal reforms to make carrying acid an offence on a par with carrying a knife.

When Parliament returns in the autumn, Ms Brown is to table legislation that is likely to seek to restrict the sale of acids and increase penalties on those found carrying the substance.

Ms Brown said there needed to be questions asked as to whether the Government’s deregulatory reforms made it easier for criminals to get their hands on dangerous acids.

“The changes that the Tory and Liberal Democrat Coalition Government introduced in their 2015 Deregulation Act removed any requirement for sellers of corrosive substances including concentrated forms of sulphuric acid to be registered with local councils”, she told The Independent.

“We need to understand if the changes have allowed criminals to buy these dangerous chemicals for very low prices and with no realistic safeguards in place. The experts who sat on the former ‘Poisons Board’, who had responsibility for advising the Government on this, voiced concerns about these changes, but the Tories and their allies went ahead regardless.

“I will be pushing for changes to these laws over the coming months. I am continuing to consult with independent experts and campaigners, and with the police and other emergency service workers, to find better ways to keep these chemicals out of the hands of criminals. The Government needs to act quickly so that our communities are made safe from this threat.”

In addition to dangerous chemicals being sold in shops, high-strength acids are now widely available online. Amazon, for example, has numerous listings for 500ml bottles of “laboratory grade” sulphuric acid. A litre of the potentially lethal substance can be purchased for just £14.99.

The Home Office declined to comment on the 2015 changes but said it was now looking at how to restrict the sale of acids. A spokesperson said: “Acid attacks are horrific crimes which have a devastating effect on victims.

“Last week we announced a new strategy to reduce the number and impact of these vile crimes.