Merseyside is the ketamine capital of the North West, the latest figures on drug seizures reveal.
The Police Federation has warned that a "proliferation of illicit drugs on the streets of the UK" is being used to fund serious crime, following the first rise in seizures across England and Wales for seven years.
Merseyside Police made 43 seizures of ketamine in 2018-19, according to figures released by the Home Office.
At 30 seizures per million residents, it was the highest rate among the five police forces in the North West.
Ketamine is a hallucinogenic substance, used as a pain killer or anesthetic in the medical field but categorised as a Class B drug when used illicitly.
Possession carries a maximum sentence of five years in prison plus an unlimited fine, while those caught supplying it could face a 14-year spell behind bars.
Across England and Wales, seizures of ketamine increased by 32% over the course of the year.
Overall, Merseyside Police recorded 655 drug seizures during the year, an increase of 13%, and the second consecutive annual rise.
The figures mean there were 460 seizures for every million residents, far lower than the rate of 2,432 per million across England and Wales.
The most frequently seized drug was cannabis (349) followed by cocaine (127).
Across England and Wales, the number of drug seizures increased for the first time since 2011-12.
Police and border forces recorded 153,000 seizures, an increase of more than 16,000 in one year, but still far lower than the peak of 241,000 seen in 2008-09.
Labour MP Jeff Smith, co-chair of the all-party parliamentary group for drug policy reform, said the figures were "little reason to celebrate".
"The illicit drugs market is resilient to the extent that a major bust is only likely to disrupt supply for a matter of hours," he said.
"With UK drugs-related death figures the highest on record, the Government’s approach to drugs policy is doing nothing to avert the public health crisis we face.
"The real priority should be to focus on education and to bring in harm-reduction measures that will save lives."
Simon Kempton, operational policing lead for the Police Federation, said the figures demonstrate "the importance of all law enforcement agencies in the UK working in a joined up way" to tackle organised crime.
He added: "These figures also reflect the huge amount of drugs which are available, as both prices and purity of drugs available on the street don’t seem to have been affected.
"This is a concern which underlines how there is a proliferation of illicit drugs on the streets of the UK, all