New immigration proposals, setting minimum earnings of nearly 20,000 for those wanting to bring a relative to the UK, would prevent up to 30,000 parents and children from joining their families here.

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The right to a family life is enshrined in article eight of the European convention on human rights, however, so any UK parliamentary motion would be a direct challenge to British judges, whose job is to apply the law independent of parliament.

"In a democratic state where judges are appointed to act independently of government, it is inconceivable that the secretary of state should be seeking to remove the independent judicial thinking," Jawaid Luqmani, a London-based expert in public law and immigration law, told Channel 4 News.

"In theory there is no change. However, in practical terms it may mean that judges - who often reflect public opinion, in the longer term more so than politicians - will no doubt feel some degree of pressure on a further challenge to their decision making," Mr Luqmani said. "I would hope that many judges will be able to remain oblivious to the threat."

Separation of powers

Any law amending the human rights act or the proper application of judicial thinking or approach would almost certainly be contrary to the convention, lawyers said.

"One may be forgiven for some degree of cynicism as to the rationale for the motion and also whether it is intended to create a change in attitude rather than a change in application," Jawaid Luqmani told Channel 4 News.

Ms May said she wanted MPs to clearly set out their view on what constituted the right to family life and how to balance the public interest against individual interests.

Immigration Minister Damian Green said: "We will shortly be announcing a major overhaul of the existing family migration rules, to reduce burdens on the taxpayer, promote integration and tackle abuse."

The reforms are also designed to protect the public from foreign criminals who try to abuse human rights laws to avoid deportation.

"We plan to make it clear when the rights of the law abiding majority will outweigh a foreign criminal's right to family and private life," he said.

Up to 30,000 parents and children would be prevented from joining their families in the UK because they are too poor, under proposed new immigration rules.

Home Secretary Theresa May is to set a minimum earnings level of nearly £20,000 for anyone wanting to bring in a spouse or son or daughter. The government also wants to make it easier to deport foreign criminals.

Ms May will outlines the details to parliament on monday.According to estimates from independent government advisers on migration, the £18,600 minimum ssalary would mean a 45 per cent reduction in family members settling in the UK.

According to Home Office figures, family migration currently amounts to 18 per cent of all immigration outside of the EU. In 2010 over 65,000 people were given settlement status.

The home secretary hopes the move will have an impact on reducing net migration to the UK to tens of thousands by the next election. But opponents see it as an attack on the right to family life, giving some British citizens with foreign partners the difficult choice of exile abroad or long, enforced periods of separation from loved ones.

'Not an absolute right'

"This (family life) is not an absolute right," Ms May told BBC's Andrew Marr show on Sunday. "In the interests of the economy, or controlling migration or public order, those sorts of issues, the state has a right to qualify the right to a family life."

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