Keir Starmer’s government has been accused of trying to water down legal protections for torture victims as ministers from 46 countries including the UK prepare to make it easier to deport refused asylum seekers and foreign criminals.

Yvette Cooper, the foreign secretary, is expected to agree a “political declaration” on Friday with other members of the Council of Europe, which oversees the European convention on human rights (ECHR).

The declaration is supposed to curb the way the convention is interpreted by European and domestic courts to halt the removal and deportation of asylum claimants.

It follows claims from Cooper and the home secretary, Shabana Mahmood, that articles 3 and 8 of the convention – the right to live free from torture and the right to family life – have been misused by criminals.

Reacting to the planned declaration, legal experts and human rights organisations said the move was a “grubbily political deal” that risked playing into the hands of repressive governments.

Prof Eirik Bjorge KC, the author of Courts as Faithful Trustees: Domestic Application of the ECHR, said the declaration sought to interfere with the independence of the judiciary but would be rejected by judges.

“There is nothing principled about the Chisinau manifesto; it is a grubbily political initiative. Seeking to water down by political means the most fundamental guarantee in the ECHR, the absolute prohibition in article 3, is ignoble and unlikely to have any effect on the jurisprudence of the Strasbourg court.

“The initiative seeks to interfere with the independence of the judiciary and will be rejected as such,” he said.

Kolbassia Haoussou, a director at the NGO Freedom from Torture and a torture survivor, said: “The UK has long prided itself on fairness, compassion and upholding the rule of law. Chipping away at article 3 would not just undermine that reputation but send a dangerous message to repressive regimes around the world that even the most fundamental protections can be bargained away. Every safeguard dismantled today will be a gift to those who seek to abuse power tomorrow.”

The UN Committee Against Torture last week expressed concerns that efforts to overhaul the convention were undermining the absolute nature of the prohibition of inhuman and degrading treatment.

Reacting to the criticism, UK government sources denied that torture victims would be affected by the change, saying that “absolute protections” would remain.

Cooper will sign the declaration in Chișinău, the Moldovan capital, accompanied by the attorney general, Richard Hermer.

It is expected to set out a list of clarifications in the way that the convention should be interpreted by the European court of human rights in Strasbourg, the ultimate arbiter of the convention, and by national courts.

The political agreement has been negotiated by member states over the last year in response to growing concerns over the way in which the ECHR is being interpreted by the courts.

The government has claimed that serious criminals have exploited the system to frustrate their deportation and extradition, and abused family rights under article 8 of the convention.

International law experts, including Prof Veronika Fikfak of University College London and Prof Mikael Rask Madsen of the University of Copenhagen, said the council’s declaration appeared to be a “signalling exercise” to warn courts to “back off”.

“States could have, for example, asked the [European] court for an advisory opinion on protections in the field of migration, but they chose not to do so. Perhaps this is then mostly a signalling exercise to the court to back off.

“Without legislative action, what was agreed at international level is then unlikely to have any bite at home.

“The declaration might better be understood as a stepping stone to hardening domestic stances on migration and creating a common political position,” they said in a joint statement to the Guardian.

European ministers will also discuss plans to send thousands of refused asylum seekers to third-country hubs.

Alain Berset, the secretary general of the Council of Europe, told the Guardian that discussions about the removal of people who arrived in Europe by irregular routes would take place “at a multilateral level”.

Starmer’s government has attempted to set up “return hubs” after the rise of Reform UK in the polls. Mahmood told MPs in November that the Home Office was in “active negotiations” with several countries, but no deals have been confirmed.

The king’s speech on Wednesday promised a new immigration bill including the tightening of the application of article 8 of the convention.

In a statement, Cooper said: “We have been working with neighbours across Europe to ensure that countries can take strong action against illegal migration, control borders, uphold the rule of law and respect international standards.

“The ECHR has protected democracy, human rights and the rule of law across Europe for 75 years. To ensure this continues, we need a commonsense approach that reflects the realities of today.”