The Liberal Democrats are likely to adopt as official policy a move to quash all historical sex-work convictions – including brothel-keeping, soliciting business and kerb-crawling.

The move to wipe convictions from people’s records will be included in a key motion at Lib Dem spring conference as part of the party’s wider drive to decriminalise sex work, while strengthening laws against “non-consensual” activity.

It will also cement official policy to oppose Government plans to introduce an age-verification process for people wishing to access online pornography, currently passing through the House of Lords.

Lib Dem Leader Tim Farron thinks the quashing of all previous convictions is a critical element in the drive to decriminalise sex work, something which overall will help reduce risks faced by women and men in the industry.

The party’s home affairs spokesman Lord Paddick said: “As a former police officer I know what works and the current laws around prostitution do not. They might sound tough but they don’t protect people. The police should be focusing their resources on the very real crimes of trafficking and coercion rather than policing consenting adults.

“Sex workers face enormous discrimination and are more likely to fall victim to crime and violence simply because the law criminalises them. We should target our policies and efforts at reducing harm not wasting police time and creating barriers that stop vulnerable people seeking help.”

The former Metropolitan Police Deputy Assistant Commissioner said: “That's why Liberal Democrats are proposing to take these outdated laws off the statute book. I believe it is time for an informed debate on this complex issue and I want my party to be leading that debate.”

The motion to be voted on at the conference in late March would “quash past convictions for anything that would be decriminalised under the new system”.

In pictures: Sex workers protest in Paris Show all 8 1 /8 In pictures: Sex workers protest in Paris In pictures: Sex workers protest in Paris A protester (R) holds a sign reading 'Prostitutes with fists raised against the penalisation of clients!' during a demonstration by sex workers and supporters near the French National Assembly in Paris In pictures: Sex workers protest in Paris A protester wears a hat rimmed with red roses during a demonstration by sex workers and supporters near the French National Assembly in Paris In pictures: Sex workers protest in Paris Sex workers hold signs during a protest against new bill against prostitution and sex trafficking In pictures: Sex workers protest in Paris Transgender sex workers protest against a parliamentary vote to enforce the penalisation of solicitation, near the Assemblee Nationale (French parliament) in Paris In pictures: Sex workers protest in Paris A protester wears a mask during a demonstration by sex workers and supporters near the French National Assembly in Paris In pictures: Sex workers protest in Paris Protesters wear masks during a demonstration by sex workers and supporters near the French National Assembly in Paris, as French lawmakers take part in a final debate on a bill that would make it illegal to pay for sex. French lawmakers were poised on April 6 to pass a controversial law that makes it illegal to pay for sex and imposes fines of up to 3,500 euros ($3,970) on prostitutes' clients In pictures: Sex workers protest in Paris Protesters hold up their fists and chant slogans during a demonstration by sex workers and supporters near the French National Assembly in Paris In pictures: Sex workers protest in Paris Protesters hold a banner reading 'Don't liberate me, I'll take care of it myself!'

That would include brothel keeping, which the party believes prevents sex workers from getting together to work in a safe space, solicitation, seen as something that pushes sex workers to take risks to secure business, and also kerb-crawling.

As well as decriminalising sex work activity, the motion seeks to refocus laws on tackling “non-consensual activity” including trafficking, child prostitution and pimping, and would see a strengthening of measures against “coercion into sex and sex work on the grounds of fear, force, or fraud”.

In addition, the policy would set up additional support for people trying to leave sex work, including through housing authorities, healthcare providers and places where education and training are available.

The Digital Economy Bill, which continues its passage through Parliament this week, will force pornographic websites to add age-verification checks that will not let people watch videos until they sign up through a special process, that would involve giving personal details.

But the motions says the party believes the checks to be “illiberal, to pose a severe danger to privacy, and to be fundamentally unworkable”.

There have been a string of hacking attacks on internet pages, such as dating websites, which have seen people’s personal data stolen, spread across the internet and even used as means for blackmail.