Jail terms for paedophiles convicted of the "grooming" of children will be a maximum of ten years - after MPs agreed a radical shake-up of sex crime laws which date back to Victorian times.
A maximum jail sentence of seven years had been planned
Ministers have decided to increase the maximum sentence from seven years after a series of high profile cases.
An amendment making the change has been added to the Sexual Offences Bill, which received an unopposed third reading in the House of Commons and returns to the House of Lords for further consideration.
But MPs rejected a bid to grant anonymity to suspected
The flagship bill will revamp the UK's current "archaic, incoherent and discriminatory" laws and includes measures on rape, voyeurism and legal definitions of consent.
Under the new "grooming" offence it is illegal for adults to meet or arrange to meet someone under 16 to engage in sexual activity.
The new offence is aimed at targeting paedophiles who try to contact children on the internet, but it would also cover adults in contact with children for legitimate reasons who try to move the contact on to a sexual level.
There have been a number of high profile cases involving men who "groomed" children via the internet.
Last month, three judges in the Court of Appeal increased the jail term of a man who had sexually abused two 13-year-old girls.
They ruled that the three year sentence given to electronics engineer Michael Wheeler at Norwich Crown Court in June was "significantly too lenient".
They increased the sentence by 18 months.
In another case, Douglas Lindsell, 64, of Twickenham, south-west London, was last month given a five-year prison sentence for a series of offences.
He was found with a hand-written sexual profile of 54 youngsters from the UK and 19 from abroad.
Some of the girls received up to 100 telephone calls from Lindsell after he befriended them via the internet.
Last month Junior Home Office minister Paul Goggins told BBC News Online that the new "sexual grooming" offence would "for the first time, protect children from the use of the internet by paedophiles - making it an offence to meet or arrange to meet a child with the intention of committing a sexual offence".
In the Commons on Monday, he added: "Clearly we would all be relieved that the offence of actually carrying out the sexual assault did not take place, but in such cases a maximum sentence of seven years imprisonment may not be adequate."
Dominic Grieve, for the Tories, told the minister: "I welcome what the government has done wholeheartedly and I am most grateful to you for having taken on board the representations and points that were made."
A Home Office spokeswoman said: "We have decided to raise the penalty for the
grooming offence following a convincing debate in committee where strong
arguments were advanced for raising the penalty to enable appropriate sentences
to be passed in the most serious cases."
Under the new proposed laws, stricter sentencing would also apply to the offence of indecent assault.
The previous maximum 10-year sentence could, in some cases, be extended to life.
Sex with a child under 13 would automatically be classed as rape and carry a maximum life sentence.
Sex in toilets
In addition, the bill includes a risk of sexual harm order, which proposes that those registered as sex offenders would be required to confirm their details annually.
Similarly, the period within which an offender should notify the register of any changes would be reduced from 14 days to three.
Measures will also be introduced to ensure offenders who travel to or from the UK will be more effectively monitored.
Mr Goggins said the government believed current legislation already covered the
outlawing of sex in toilets.
Ministers originally removed the proposed offence of "sexual activity in a public place" from the bill after concerns raised by the Police Federation.
Police had feared the plan would make it harder to prosecute incidents of sex in public toilets in cases where cubicle doors were closed.
Mr Goggins said: "The government believes sexual activity in toilets is wholly
Other proposals unveiled include protection for the police and other security organisations from being caught by laws against downloading pornographic images.