Ministry of Justice data reveals that 180 searches uncovered drugs within HMP Winchester in the year to March – significantly up from 37 the previous year.
It was also the highest number since comparable records began in 2016.
Officers also discovered mobile phones on 33 occasions, alcohol 40 times, and weapons on 70 occasions.
Across England and Wales, the number of drug finds in prisons fell 6 per cent to 20,300 in 2020-21 – a reduction Her Majesty's Prison and Probation Service has linked to restrictions placed on prisons during the pandemic.
But some prisoners have turned to using drugs due to chronic boredom and isolation made worse by the Covid-19 pandemic, a report from the prisons inspector discloses.
In an annual report for 2020-21, Her Majesty's Inspectorate of Prisons for England and Wales said out of 70 prisoners interviewed across six prisons, most had spent the pandemic locked in their cells for more than 22 hours a day.
Frances Crook, chief executive of penal reform charity the Howard League, said drugs remained a ‘scourge’ in prisons.
She added: ‘They have a devastating impact on the lives of prisoners and their families, and we know that the number of confiscations recorded even before the pandemic did not tell the whole story about the true scale of the problem.’
The charity is calling on the government to focus less on tightening prison security and more on building relationships and working with prisoners through training and exercise to combat the issue.
HMPPS said in 2016 it had increased measures to target the supply of banned items in prisons, but mandatory random drug testing has been severely disrupted during the pandemic year.
A Ministry of Justice representative said: ‘Our £100 million investment to bolster security through X-ray body scanners and extra searches continues to stop drugs getting into the hands of prisoners.
‘This is part of wider funding to make jails safer, while working closely with healthcare providers to ensure offenders have the support they need to live drug-free upon release.’