The remaining provisions of the Psychoactive Substances Act 2016 will not enter force until at least May, The Guardian reports.

The Home Office has backed down from an earlier commitment to implement the ban on so-called “legal highs” by 6 April 2016.

Karen Bradley, parliamentary under-secretary of state in the Home Office, gave a written answer to questions in the House of Commons regarding the implementation of the law.

Ms Bradley wrote: “We expect to commence the Psychoactive Substances Act in its entirety in the spring.

“We need to ensure the readiness of all the activity necessary to enable the smooth implementation of the legislation across the UK and to support law enforcement in their ability to drive forward the legislation on commencement.”

However, the Home Office must give 21 days’ notice to Parliament before implementing the remaining provisions of the law.

Due to the dates when Parliament is sitting, this means the earliest possible date for implementation is 1 May 2016.

Northern Ireland’s Justice Minister David Ford earlier said the Department of Justice will work with the Home Office to “prepare for commencement of the new law in the spring of this year”.