CONTROLLING post-Brexit immigration will be a struggle for the Government if it continues to rely on "woefully inadequate" information, a Lords report has said.

The upper house's Economic Affairs Committee found that current data does not provide an accurate picture of how many migrants enter or leave the country each year, or how long they stay.

The Government will be making immigration policy "in the dark" unless it overhauls the way statistics are collected, peers said.

Committee chairman Lord Forsyth of Drumlean said: "The Government must have reliable statistics on migration before it formulates new policy, otherwise it will be making crucial decisions - of vital importance to the country's businesses - in the dark.

"It will take companies time to adapt their business models to be less dependent on EU workers and an implementation period is essential to ensure a smooth transition."

Lord Forsyth said that reduced immigration may lead to higher prices.

He said: "Businesses will have to accept that immigration from the European Union is going to reduce and adapt accordingly. Some firms will need to raise wages to attract domestic workers.

"In other sectors, where migrant workers may not easily be replaced by domestic workers, firms will need to change their business models or increase capital investment in automated processes. All these options may lead to higher prices for consumers.

"The committee's 2008 report on immigration warned that the employment of migrant workers could lead to businesses neglecting skills and training for British workers. As the recruitment and retention problem in the nursing sector highlights, these fears have been realised and training for the domestic workforce needs urgently to be given a higher priority."

Peers said that the current data system cannot accurately state how many foreign students remain after their courses end.

The committee said the Government needs to address this problem, and then no longer include students in any short-term net migration figures for public policy purposes.

Peers called for the Government to use information relating to the economic activity of immigrants - such as paying tax or receiving benefits - to gain a clearer understanding of how long migrants stay in the UK.

The committee said Government policy of using a strict annual numerical target for immigration risks causing disruption to businesses and the economy.

It called for a flexible approach which can adapt to the needs of businesses and the labour market, in particular during any implementation period.

A Government spokesman said: "We are collaborating with the Office for National Statistics to develop a system which provides a richer statistical picture of EU nationals in the UK.

"The Government is also working to develop a future immigration system which acts in the country's best interests and we will ensure businesses and communities are given the opportunity to contribute their views.

"In addition, the Home Secretary has made clear the Government will ask the Migration Advisory Committee to provide evidence on EU migration precisely because we want strong evidence on which to base these important decisions."