Yulia Skripal has been discharged from a British hospital, just over a month after being poisoned with a nerve agent along with her father Sergei, a former Russian double agent.

BBC News said on Tuesday the 33-year-old Skripal had been discharged from hospital and taken to a "secure" location on Monday.

Britain's Press Association says hospital officials plan to make an official statement in the high profile case.

The British government is likely to keep details about her location secret given the sensitivity of the ongoing investigation.

The Skripals were found unconscious on a bench on March 4 in the southern English city of Salisbury and they were in a critical condition for weeks until their health began to improve rapidly.

Yulia had arrived on an Easter visit from Moscow the day before the attack which was apparently aimed at her father who remains hospitalised.

On Friday, doctors said both Yulia, 33, and her 66-year-old father had responded to treatment and last week Yulia issued a statement to say her strength was growing daily.

Britain blames Russia

Britain says the father and daughter were poisoned with a military-grade nerve agent and has blamed Russia for the attack. 

Moscow has denied any involvement in the incident which has plunged its relations with the West to a post-Cold War low.

The incident led to the expulsion of diplomats on both sides.

Britain has been backed by the United States and its European allies in blaming Russia for the assault.