Britain's oldest ally and one of Bristol's strongest ties were honoured with the naming of a new quayside in the city's historic harbour.

For more than 500 years, trade has flourished between Bristol and the Portuguese city of Porto.

The Bristol Record Office has evidence of three ships from as long ago as 1309 arriving from Portugal, bearing figs and raisins, and a fervent trade in other goods soon followed, principally in port.

And yesterday the current Portuguese ambassador, His Excellency Senor Antonio Santana Carlos, made his first visit to Bristol for the official naming of Porto Quay.

The relationship between the two cities was officially recognised with a twinning arrangement in 1984, and has now been cemented further with the naming of the quay, which is part of the regeneration by Crest Nicholson on the former Canon's Marsh area, opposite the ss Great Britain.

Lord Mayor of Bristol Christopher Davies welcomed the ambassador to Bristol and read a letter from his recently re-elected counterpart in Porto, Mr Rui Rio, who thanked the city for the "great honour" of naming the quay after Porto.

Alderman Marmaduke Alderson, chairman of the Bristol Oporto Association, pointed out the importance of the connection to the Portuguese by revealing the Post had been scooped by the Porto papers, who had proudly published pictures of the sign yesterday morning before its official unveiling.

Mr Alderson also presides over the Bristol Oporto Foundation, which promotes projects in Bristol schools relating to Portugal and has sponsored students to travel to Portugal to learn the language. It is continuously working on furthering links with the 500-strong Portuguese community in Bristol.

The ambassador honoured his official duty of unveiling the sign after a sunny boat ride around the harbour from cascade steps, and stayed for a considerable period afterwards mingling with local dignitaries over a glass of port.

"This is a great day for the relationship between Portugal and Britain, Porto and Bristol," said Mr Carlos. "I have been well received. It is a beautiful waterside city, like Oporto."

His chauffeur busied himself with a book of sudoku in the sunshine while representatives from the developer Crest Nicholson, its surveyors King Sturge and legal team CMS Cameron McKenna entertained the ambassador and talked him through the extensive redevelopment of the area.

More than 500 apartments have been built by Crest Nicholson on the Canon's Marsh site, and with just 59 still unoccupied there is cautious optimism that the property market might be recovering; enough at least for the firm to consider starting work on planned further commercial and residential buildings on the site where work began in 2004.

In January, Hargreaves Lansdown will be relocating up to 800 employees to a purpose-built block there, which is expected to bring new life to the area and help spur further development.

The ceremony continues a tradition of naming the new quaysides after Bristol's twin cities, following Bordeaux Quay in St Augustine's reach, and Hanover Quay alongside the Lloyds TSB headquarters.