UK construction and services company Carillion, which is involved in six projects in Ireland, has collapsed after banks refused to lend it any more money.

It throws hundreds of major projects in doubt and brings down one of the UK government's most important suppliers. 

The company is involved in six projects in Ireland, including five schools and the Carlow Institute of Further Education.

It was responsible for the design, build, finance and maintenance of the six buildings on four sites in Meath, Carlow, Wicklow and Wexford.

It also has contracts in Northern Ireland with the Housing Executive and Power NI, which involves around 230 engineers and service providers.

Carillion is responsible for heating nearly 40,000 Housing Executive properties and the building maintenance of more than 20,000 homes.

Carillion was forced into compulsory liquidation after costly contract delays and a downturn in new business.

It prompted a string of profit warnings and a first-half loss of more than £1 billion.

"In recent days we have been unable to secure the funding to support our business plan and it is therefore with the deepest regret that we have arrived at this decision," Chairman Philip Green said. 

"This is a very sad day for Carillion, for our colleagues, suppliers and customers that we have been proud to serve over many years," Mr Green added. 

Carillion's creditors include RBS, Santander UK, HSBC and others. It has debt and liabilities of £1.5 billion.

Employing 43,000 people around the world, including 20,000 in Britain, the 200-year-old company runs public services from hospitals to train lines and ministry of defence sites. 

It has also built construction projects such as London's Royal Opera House, the Suez Canal road tunnel and Toronto's Union Station.

Read More: 

Carillion collapse should not hit school projects: NDFA 
A timeline of Carillion's collapse

In July last year it won contracts to build Britain's new High Speed 2 rail line, a major project that will better connect London with the north of England. 

Tension around Carillion has been ratcheting up for weeks, forcing the UK government to hold a string of crisis meetings to discuss how they should respond.

Unions have argued that taxpayers should not bail out the failing company. 

Carillion said the government would provide the necessary funding to maintain the public services carried out by its staff, while PricewaterhouseCoopers will oversee the process.

Carillion was part-way through constructing a major new hospital in the West Midlands when it announced it was entering liquidation.

The company had been the constructor for the new Midland Metropolitan Hospital in Smethwick and work was expected to be completed at the new site in 2019.

The company also held a number of contracts to provide facilities services at other NHS trusts which include maintenance, cleaning work, portering and catering.

The company's website says it prepares over 18,500 patient meals per day.

It is understood between ten and 15 NHS trusts in England have ties to the company.

Measures are also being taken to secure the future of 1,400 Carillion apprentices following the company's collapse.

Britain's Construction Industry Training Board said today's development will have a "huge impact" on the company's thousands of employees and their families.

The board said it was setting up a project team to prioritise the retention and redeployment of apprentices.

Meanwhile, services at hundreds of schools could face uncertainty as the firm provides meals as well as cleaning contracts and maintenance services to many schools across the UK.

Headteachers said that schools should not encounter problems as the government has announced it will deliver public sector services, but added that they will be "monitoring the situation closely".

According to the firm's website, it delivers more than 32,000 school meals every day to UK primary and secondary schools.

It also says it cleans over 468,000 square metres of property across 245 schools, provides mechanical, electrical and fabric maintenance services to 683 schools and facilities management to 875 schools.