Construction industry experts have raised concerns about the quality of Scotland's largest hospital following the death of two patients.

The Queen Elizabeth University Hospital (QEUH) in Glasgow opened in 2015, bringing five facilities under one roof - the Western Infirmary, Victoria Infirmary, Southern General, Mansionhouse Unit and the Yorkhill sick children's hospital.

But it has been marred with issues ever since, including a sewage leak, the discovery of fire-hazardous cladding and the deaths linked to pigeon droppings.

An independent inquiry has been commissioned by the Scottish Government into the £850m building project, while a recent Healthcare Improvement Scotland inspection raised cleanliness concerns.

STV News has spoken to an architect who worked on the project, who says he predicted the problems faced by the 'super hospital'.

The expert, who asked not to be named, said he was surprised when the contract to build the 1109-bed QEUH - which also boasts a 256-bed children's hospital and 30 operating theatres - was won by developer Brookfield Multiplex.

Three bids were made for the contract and, in 2009, NHS Greater Glasgow and Clyde said the winning proposal provided "the best value for money".

It was completed under budget and five weeks ahead of schedule, but less than a year after it was opened by the Queen, issues started to emerge.

Healthcare architect Christopher Shaw has worked on large academic medical hospitals in Europe and across the world.

He is complimentary of the design, in particular the single rooms providing privacy as well as the shape, allowing good levels of daylight.

But he believes the very nature of trying to build a 'super hospital' creates complexity.

Mr Shaw, from not-for-profit organisation Architects for Health, said: "This is a whole step up from the normal hospital.

"It is 1600-1700 beds, it is vast so it is inevitable that in a complex design, construction, commissioning and operation of a system like that that there may be mismatches and things that don't work as designed.

"I think because the health service is loved, it's very prominent politically, it's in everybody's minds [that] we like our NHS and we love our hospitals, but any problems with it will get into the public eye and in this case there have been some tragic deaths which have obviously been a problem and that has raised the profile of it."

NHS Glasgow defended the tendering process for building the hospital and said it was responding to the Healthcare Improvement Scotland inspection findings.

Robert Kincaid, an electrician in the construction industry for 40 years, recently left a job on a new hospital in Orkney because of concerns about poor workmanship.

The company he was sub-contracted to work for - Robertson - was also involved in the Queen Elizabeth University Hospital.

He described the physical standard of the new £64m Balfour Hospital in Orkney as "extremely poor".

Mr Kincaid added: "I don't want to be a part of that build in Orkney because down the line it's going to come to the same position as the Glasgow hospital.

"They'll find faults, faults will develop, there's no doubt in my mind about that because of the standard of work.

"It's extremely poor and it's almost embarrassing now to be part of the construction industry it's that bad."

Robertson and NHS Orkney dismissed his concerns, with the health board insisting it had the "utmost confidence" in the building firm, which said it placed a "huge emphasis on ensuring quality at every stage of our projects".

NHS Greater Glasgow and Clyde: "Our own internal review has been set up and is ongoing, with support from industry experts. This review is examining a range of issues including the design, commissioning and maintenance of the Queen Elizabeth University Hospital and Royal Hospital for Children. We are also contributing to the external review set up by the Cabinet Secretary for Health and Sport. The process to appoint contractors for the Queen Elizabeth project went through various detailed stages of dialogue and competitive procurement, fully in line with Scottish Government procurement policy and the European Union Procurement Directive. We place the highest priority on the issues raised through the recent inspection by Healthcare Improvement Scotland and significant work has been undertaken in relation to all the issues in the report."

Ann McCarlie, project director at NHS Orkney: "We have the utmost confidence in Robertson and the work they are undertaking. We have worked in partnership with them over the last two-and-a-half years. There has been considerable scrutiny of the works, including by an independent Clerk of Works. We are confident that any issues have been - or are in the process of being - rectified."​​​

George Young, project director at Robertson: "Robertson places a huge emphasis on ensuring quality at every stage of our projects and we also demand exceedingly high standards from our sub-contractors. All construction works at The Balfour are being carried out in accordance with the project specification, drawings and industry quality standards, as confirmed by both our own employees and also third party verifiers. We are extremely proud of our involvement at The Balfour and are grateful to NHS Orkney for the opportunity to deliver an already award-winning project. Once complete, the new facilities will transform healthcare for those on the island and we look forward to handing over the facilities on time and on budget."

Scottish Government: "The Health Secretary has announced an independent inquiry that will look in detail at the design, commissioning, construction, handover and maintenance of the Queen Elizabeth Hospital. Co-chairs Drs Brian Montgomery and Andrew Fraser will confirm the full remit of their review in due course. An unannounced inspection by Healthcare Improvement Scotland, also carried out at the instigation of the Health Secretary, has now been completed, and we expect NHS Greater Glasgow to take action to address the issues that were raised in the report."

Brookfield Multiplex, the firm which built the Queen Elizabeth University Hospital: Did not reply to a request for comment.

March 2016: Sewage leak led to operations being cancelled.

August 2017: Following on from the Grenfell fire in London, it is announced hazardous cladding on the QEUH will be removed.

March 2018: Four children received treatment for infections linked to a bacteria found in the water supply.

August 2018: Last summer a glass panel shattered and fell.

October 2018: It was announced that 16 children had their cancer treatment delayed following a bacteria outbreak in the drains.

January 2019: Prosecutors announced they're investigating the deaths of two patients who had contracted an infection linked to pigeon droppings.