LONDON, March 6 (Xinhua) -- The way Britain ends free movement of people post-Brexit could have a far-reaching impact on a future trading relationship with Europe, a report from Westminster warned Monday.

Offering preferential treatment to EU nationals than non-EU nationals in Britain's future immigration regime could increase the likelihood of securing reciprocal preferential treatment for British nationals in the EU, says the House of Lords EU Home Affairs committee in its report.

The report adds that it could also improve the prospects achieving Britain's objectives on access to the European single market.

The report has been published against a background of Prime Minister Theresa May's comments that the public had delivered a message that Brexit must mean control of the number of people who come to Britain from Europe.

"In order to deliver this, the government intends to put an end to the free movement of persons, one of the four freedoms underpinning the single market," says the report.

The committee has examined possible arrangements for migration of EU citizens to Britain after leaving the EU with a view to identifying the main choices available, and the likely implications, including for British citizens wishing to move to the EU in future.

Baroness Prashar, who chairs the committee, said "The precise manner in which the government proposes to end free movement is a pivotal aspect of the United Kingdom's approach to negotiations with the European Union and could have far-reaching consequences for the UK's future trading relationship with the EU."

In its findings, the committee says it's vital the government not close off policy options on future regulation of EU immigration ahead of negotiations with the remaining member states, known as the EU27.

"Some of the most significant policy choices facing the government will be about how to treat EU nationals in non-work categories and about the terms and conditions of residence for EU nationals as a whole. In other words, whether they should continue to receive treatment on par with UK nationals," said the report.

It added that the restoration of national control over EU migration may or may not deliver a reduction in overall net migration, noting that until June 2016, net migration to Britain from outside the EU was consistently higher than EU migration, even though the relevant policy levers are already under national control.