When police searched his parents’ Prenton home after discovering the drugs, they found a gun Maguire had hidden in their back garden without them knowing.
Alongside the semi- automatic pistol were nearly 300 bullets, 93 of which were “expanding rounds” designed to cause as much damage as possible on impact with their target.
A Merseyside Police spokesman said: “We can confirm that a serving police officer from Wirral has been suspended as part of an investigation into an allegation of misconduct.
“The officer, who is 48 years old, was suspended in December 2011, while the allegation is investigated.
“As the matter is currently under investigation it would be inappropriate to comment any further.”
A Wirral council spokeswoman said: “This driver appeared before the panel more than 12 months ago and was granted a licence to operate as a private hire driver.
“His licence has subsequently been renewed for a further 12 months. We are not aware of any alleged impropriety surrounding his initial application for a private hire licence but we would, of course, assist with any investigation if requested and take action to review his licence if necessary.”