It would be "completely inappropriate" for the Government to host talks with Egyptian president Abdel Fattah al-Sisi later this year after a court in his country sentenced three Al-Jazeera English journalists to three years in prison, one of the reporters said.
It was announced in June that there will be bilateral discussions later this year with the former head of Egypt's armed forces, who led the coup overthrowing Islamist president Mohammed Morsi.
But Australian journalist Peter Greste, who was deported from Egypt in February, told Channel 4 News that the planned visit "doesn't seem compatible with putting him under pressure".
He added: "It seems completely inappropriate in the light of this conviction. The whole world has been watching this case very very closely to see Egypt's commitment to freedom of the press, rule of law, due process. What we are seeing today in these convictions is a gross injustice and a violation of all of those very fundamental principles.
"For President Sisi to be sitting alongside the Prime Minister of Britain is going to send out a very negative message.
"What we need to do is make it very clear that President Sisi now has an opportunity to right an injustice, and send a message back to the world that Egypt does pay more than just lip service to those principles."
The case against Mr Greste, Canadian national Mohammed Fahmy, and Egyptian producer Baher Mohammed embroiled their journalism into the wider conflict between Egypt and Qatar following the 2013 military ousting of Mr Morsi.
Mostefa Souag, Al-Jazeera English acting director-general, said today's court decision defied logic and common sense.
"The whole case has been heavily politicised and has not been conducted in a free and fair manner," he said in a statement.
"There is no evidence proving that our colleagues in any way fabricated news or aided and abetted terrorist organisations, and at no point during the long drawn-out retrial did any of the unfounded allegations stand up to scrutiny."
The case began in December 2013 when Egyptian security forces raided the hotel suite used by Al-Jazeera at the time to report from Egypt.
Authorities arrested the trio, later charging them with allegedly being part of Mr Morsi's Muslim Brotherhood, which authorities have declared a terrorist organisation, and airing falsified footage intended to damage national security.
Since Mr Morsi was ousted, Egypt has cracked down heavily on his supporters and the journalists were accused of being mouthpieces for the Brotherhood.
Al-Jazeera and the journalists denied the allegations, saying they were simply reporting the news.
The three men were convicted on June 23 2014, with Mr Greste and Mr Fahmy sentenced to seven years in prison and Mr Mohammed to 10 years.
The verdict brought international condemnation and calls for newly-elected Mr Sisi to intervene.
Egypt's Court of Cassation, the country's highest appeals court, later ordered their retrial, saying the initial proceedings were marred by violations of their rights.
Two British journalists, Sue Turton and Dominic Kane, have previously been tried in their absence, and found guilty.
Minister for Middle East and North Africa Tobias Ellwood said: "I am deeply concerned by the sentences handed down today against journalists in Egypt. These sentences will undermine confidence in Egypt's progress towards strong long term stability based on implementing the rights granted by the Egyptian constitution.
"We have repeatedly raised this case and the restrictions on freedom of expression in Egypt with ministers and senior officials. We note that the case can be appealed, and will monitor future developments closely. It is vital that the Egyptian authorities take urgent action to resolve the position of the two British nationals in this case."
Ms Turton told Channel 4 News that it was dreadful news that Mr Fahmy and Mr Mohammed had gone back to prison, "and we will fight till our last breath to try to get them out".
She added: "The problem with my own situation, and it's nothing compared to theirs, is that I am struggling to travel to many countries where I feel I might be extradited or deported, and that's why I've now quit my job as war correspondent for Al-Jazeera, because I was going into countries not knowing whether going through airport immigration would lead to me being arrested and handed over to the Egyptian authorities."