Blues managing director Karren Brady had agreed a fee, worth a potential £3 million, with Arsenal vice-chairman David Dein at the turn of the year.
But boss Wenger put the block on the transfer only for Upson to force the issue as he is desperate for regular football.
However all that the talks actually seem to have achieved is to alert other clubs to Upson's availability. By tea-time Leeds, Manchester City and Charton were all supposedly 'interested' with Newcastle, Chelsea and West Ham being mentioned too. Leeds is the most complicated of the interests since rumours also abound that they are looking at Upson as a replacement for Woodgate who 'is reported as' moving to Newcastle for £12 million.
Which clubs have actually agreed a fee with Arsenal is anyone's guess...no doubt things will be clearer by tomorrow.
The 30-year-old midfielder has flown back to Birmingham from France to complete the formalities today, including a medical.
It is thought Blues will have to pay Marseille around £500,000 to make the move permanent in the summer.
Swierczewski, a former Marseille captain, said he was looking forward to the switch but admitted he was short of match practice because of the winter break in France.
If the transfer is completed in time, Swierczewski could play for the reserves on Wednesday against Albion.
Bruce, though, has arranged a behind closed doors friendly against Spurs on Friday to aid the recovery from injury and fitness of others.
The former Bastia star, a success in Poland's otherwise miserable World Cup in Japan and Korea, impressed on trial last week and Bruce sees him as ideal cover for Robbie Savage and Aliou Cisse.
Stephen Clemence has also been brought in to bolster the midfield but he didn't make the 16 at Blackburn Rovers on Saturday due to a lack of match fitness.
The 20-year-old Slovak star is wanted initially on loan by Bruce, who is keen to see him in outdoor action at Wast Hills this week.
Midfielder Curtis Woodhouse has yet to decide whether to accept an invitation to join Rotherham on loan. Once again the news has alerted other clubs, with supporters from Gillingham, Grimsby, Sheffield United also claiming that Curtis was moving to them.