The Conservatives have criticised the government's record on tackling gun crime after a police chief accused senior judges of overlooking mandatory sentences.

Merseyside Police chief constable Bernard Hogan-Howe said on Tuesday that the five-year sentence for carrying a firearm should be "implemented consistently".

Pointing to the murder of 11-year-old Rhys Jones in Liverpool last year, he said: "I want very heavy sentences for possession of firearms which would deter people from arming others or carrying guns themselves."

He told the Times newspaper that the "big issue" was "getting the guns out of society".

"Generally, I feel the judiciary are supportive about what we are trying to do about gun crime and we have seen some excellent sentences which send out the right message," Hogan-Howe added.

"But I would like to see that happen more consistently. Locally there is evidence of sentencing where the power has been available and not been used and that is simply wrong."

Shadow home secretary David Davis said the government had "patently failed to get a grip on gun crime".

He claimed there had been a four-fold increase in gun-related violence under Labour, adding: "The problem is, they are happy to pass tough laws in order to get a good headline only to simply not enforce them - allowing the situation to deteriorate at great risk to the public.

"As well as failing to enforce the law, our porous borders allow weapons to simply flow into the country while the government's failure to combat the scourge of drugs also fuels so much violent crime."

However, Gordon Brown said the government has "the policing and support for the police to enable us to root out gun crime".

"We had set sentencing that is very high - five years for possession of a gun - for magistrates to use," he added.

"It is tough sentencing to take action alongside more policing in hotspots, more metal detection, more undercover policing, more stop and search powers, and more surveillance."

And a spokesman for the Ministry of Justice said: "Sentencing in individual cases is a matter for the courts.

"The mandatory five-year sentence for possession of a firearm is a starting point.

"Judges must then take aggravating and mitigating factors into consideration when determining the final sentence."