Motorists and motorcyclists in Norfolk who dice with death by speeding on the county's roads could land themselves with massive fines after the government announced maximum fines could rise by as much as 300pc.

The announcement about the highest maximum limits magistrates can impose comes as police in Norfolk have urged people not to dice with death after a motorcyclist was caught speeding at 134mph on the A11 in Norfolk last month.

The maximum fine for motorway speeding could increase from £2,500 to £10,000.

Other speeding, driving without insurance and selling alcohol to a child could also see increases as part of the proposals which justice minister Jeremy Hunt said he hoped would provide magistrates with greater powers to punish offenders.

Some motoring groups said the new fines were disproportionate and could put people off challenging unfair speeding tickets, but one of those in favour is Bridget Wall, from Downham Market, who has campaigned for road-safety charities Brake and RoadPeace since the death of her only son Adam, 24, in a crash on the A47 at Wisbech in November 2002.

She said: 'I agree with high fines because I think the higher the fine the more the deterrent. I'm all for anything to deter people from speeding – but who is going to enforce it?'

Iain Temperton, team manager of casualty reduction at Norfolk County Council, said he would welcome the prospect of magistrates being able to impose bigger fines for certain offences. He added: 'I think potentially it could be a good thing if used properly. We would certainly welcome magistrates being given the tools to do the job.'

He added: 'I would suggest there's an element of the road-using population who sometimes need this sort of sanction. Clearly it's a very small element but there's a small proportion of the public who will choose to break the law and I suppose we do need a reasonable sanction against them.'

Last month, statistics obtained using the Freedom Of Information Act revealed how two drivers were caught speeding at 121mph on the A47 bypass at Kirby Bedon and on the A140 at Scole. Both were 51mph over the speed limit.

Mr Temperton, added: 'Far too many riders are killed or injured on Norfolk's roads, often as a result of their own actions. Norfolk County Council and Norfolk Constabulary work to offer a wide range of training options, including the very popular Safe Rider course.'

To take part in a Safe Rider course, call 01603 638115 or email roadsafety@norfolk.gov.uk

In other areas of the government's sentencing plans, disorderly drunks could be fined up to £4,000.

Courts will also be able to levy unlimited fines for the first time for the most serious crimes dealt with in the lower courts – such as environmental offences – which at present attract penalties of up to £5,000 or more.

Magistrates' court guidelines set out how the appropriate level of punishment should be determined according to the seriousness of the offence. The amount of fines collected reached an all-time high of £284 million at the end of 2012/13 and remains on an upward course.

The Ministry of Justice said custody would continue to be used for serious offenders and fines would not become an alternative for those who would otherwise be sent to custody.

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