More than 100 former BBC World Service journalists have written to the Egyptian Ambassador in the UK to protest the seven-year jail sentences given to Al Jazeera journalists.
The letter described the sentences as a "retrograde step for Egypt and for international journalism".
Al Jazeera Australian correspondent Peter Greste, Canadian-Egyptian acting Cairo bureau chief Mohammed Fahmy, and Egyptian producer Baher Mohammed were found guilty on terrorism-related charges and sentenced last Monday.
Mohammed was sentenced to three extra years in prison on separate charges.
The three were arrested in December as part of a sweeping crackdown on Islamist supporters of ousted president Mohammed Morsi.
The trio were accused of supporting Morsi's Muslim Brotherhood, which the authorities have declared a terrorist organisation. They also faced charges of fabricating footage to undermine Egypt's national security and make it appear the country was facing civil war. The prosecution offered little evidence to back up the charges against them.
The letter from BBC World Service journalists was delivered by hand to the Egyptian Ambassador and signed by Ken Brazier, former editor of BBC external services news and Cairo correspondent, and Bob Jobbins, former editor-in-chief of BBC World Service News and Cairo correspondent, among others.
The letter said:
Colleagues and friends of Mohamed Fahmy, Baher Mohamed and Peter Greste at the BBC World Service and BBC News & Current Affairs, including former Cairo and Middle East Correspondents and editors, newsroom producers and writers at BBC Bush House during the past fifty years, protest to the Egyptian authorities and the Egyptian judicial system against the unjust jail sentences imposed on Mohamed, Baher and Peter,all of the al-Jazeera news channel.
Whether this process is part of an Egyptian political vendetta against al-Jazeera and its Qatari owners, or an attempt to discourage journalists from the proper coverage of Egypt, or both, we can only state that it is a retrograde step for Egypt and for international journalism.
We appeal to the Egyptian judiciary and to the Egyptian president, Abdel Fatah al-Sisi, to release the al-Jazeera journalists now and thereby try to restore to Egypt its former standing in the Arab world as a nation in which all journalists could operate freely and impartially.”