Private firms could be brought in to clear Glasgow's overflowing bins
Private contractors are set to be used to clear rubbish mounting up because of strike action by Glasgow Council refuse workers.
GMB union members walked out on Monday as world leaders gathered for the UN's climate conference COP26 in the city.
The local authority said it had been left with "no option" but to explore contingency plans.
Council and union bosses met on Wednesday in a bid to try to solve the dispute over pay and conditions.
The role of contractors would be to address urgent health and safety problems, such as overflowing bins and blocked stairwells in high rise flats.
But in the meantime as workers continue their strike, domestic, commercial and street bin waste has been piling up.
One Glasgow resident, Ann Marie Richford, said every street bin was full and she worried about how bad the problem would get.
The 54-year-old told the BBC: "I think it is disgusting. If that's it now what is it going to be like in a couple of days' time?
"I watched someone just walk past and dump a bag in the street. Every bin is full."
Asked if she had a message for the strikers, she replied: "Just hurry up and stop this strike and get rid of this rubbish.
"If they don't get back to work soon it is going to get worse and worse.
"God knows what it is going to cause."
On Allison Street, just off Victoria Road, business owners are concerned about the impact of the dispute.
Mehmood Sahid, who owns the Delicious Corner Bakery, said the situation is causing him a lot of stress.
He pays £100 a month to the council for his bins to be emptied twice a week but the lid of the large black waste skip outside his business is now fully propped open by bags of rubbish.
He added: "Our bins have not been emptied since the start of last week and they are now full.
"It is not the time to strike. It is the time to support.
"It is a bad message to people coming to Glasgow from other countries."
A Glasgow City Council spokesman said: "The GMB has left us with no option but to explore contingency plans to tackle the unfolding public health and potential fire hazards that are part of the impact the strike is having on our city.
"This is not an action we consider lightly and if we were to go ahead with this it would be the first time since 2009."
The council said it had unsuccessfully appealed for "public health exemptions" during negotiations on Sunday. This included refuse collections from high rises, student accommodation and street bins.
The spokesman added: "We can't have rubbish piling up - especially when the union keeps changing the duration of the strike.
"On Sunday they told us the strike would last two or three days, today they told us eight days."
The council reiterated its belief that the strike is "unlawful" but said it hopes to resolve the dispute with continuing dialogue.
But the spokesman warned: "We will be considering recouping any public funds spent on private contractors from the GMB - as our citizens should not be penalised in the pocket for a dispute over national pay talks."
'Step up or step aside'
GMB Scotland senior organiser Keir Greenaway said: "The council has repeatedly threatened our members with anti-union laws, but if their officials had any grounds for pursuing this they would have done so.
"But let's be clear that if the council are using agency staff to try and break this strike action then they would be the ones breaking the law.
"Where is Glasgow's political leadership? The silence is absolutely deafening from the council leader Susan Aitken, and she should either step up or step aside."
Analysis by Connor Gillies, BBC Scotland consumer affairs correspondent
This row gets messier by the day. The rubbish is stacking up.
The council feels its hands are tied as the pay offer was made at a Scotland-wide level.
Sources say the GMB's demands, including reversing previous cuts to the service, are simply not doable amid an uncertain budget in the future.
The council feels this strike is unlawful and the fact it is willing to bill the GMB union to recover the costs of private contractors shows how much relations have broken down.
GMB members are galvanised. They have been on pickets over the last few days waving their flags.
Workers accuse the council of disrespecting them for years and they are fed up. COP26 was seized on as a moment to let this row play out in public and cause maximum embarrassment.
Who will blink first? Neither side wants to back down.
Earlier, climate activists and delegates as well as international trade union representatives joined the city's striking cleansing workers at a depot in Kelvinhaugh Street.
Chris Mitchell, GMB convenor for refuse and cleansing, said that making sure services were funded properly was an environmental issue.
"It is an environmental issue, cleansing, we deal in recycling obviously and food waste," he said.
"It's just unfortunate that cuts over the last 10 years, probably more so over the last four years, have been absolutely horrendous.
"If you care about the environment you have got to invest in services, but unfortunately Glasgow are just making horrendous efficiency savings as they call them, but we call them nothing more than cuts."
TUC General Secretary Frances O'Grady said: "Climate justice and social justice go hand in hand.
"While Glasgow hosts the climate summit, the key workers who keep Glasgow clean are not getting the fair pay and conditions they deserve."