Portcullis House, which opens its doors to visitors this week, is a fine building, says former heritage secretary Virginia Bottomley. But is it worth all the time and money?
As an MP, I do not underestimate the difficulty of convincing constituents that it is right for the taxpayer to have put up the £230m for a building to house 210 MPs and 200 to 300 staff – as well as the select committee and meeting rooms that make up the first floor.

But it is also hard to describe the squalor in which most MPs have to work. And for those assistants working in an MP's office, conditions have been even worse. In my own case, my secretary and two helpers have worked in an office of about 8 m2, with one window facing a noisy car park, little light and no storage – all utterly depressing.

It should be remembered that the life of an MP is extraordinarily fragmented, with one in three of them complaining of stress-related problems within three months of arriving at Westminster. There are few focal points and many MPs and their staff work in considerable isolation. What is more, the development has taken place at a time when many say there have been moves to marginalise parliament.

One of the remarkable qualities of Portcullis House is that it has been integrated with the complex of four buildings beyond Bridge Street, where about 450 MPs now work. The new office provides a focal point to this complex of buildings. Its large new courtyard below a spectacular glazed roof, with shops and trees, acts as a forum, providing places to meet informally and discuss the issues of the day. As a result, there will be a greater sense of community between MPs of all political parties. People work best and are fulfilled when they can have shared areas of congregation.

The House of Commons Accommodation Committee investigated the scheme over many years. As ever, they learned as much from other scheme's shortcomings as their successes.

  In Canberra, for example, Australian MPs are provided with their own suites, including kitchen and bathroom, as well as support offices. (That really would be too much for my constituents.) Even so, the Australian MPs had come to feel isolated. Portcullis House provides the right balance of private and shared space for MPs and their staff, and communal space, both formal and informal, for all those who work at Westminster.

Our new offices allow us to entertain parliamentarians and official delegates from around the world, and show them where we work. In the past, there simply wasn't the room to invite visitors in. Frankly, they would have been horrified by what they would have seen.

It is also hard to exaggerate the volume of correspondence today's that MPs deal with. My office handles about 250 letters a week, not to mention constant visits, delegations and meetings. New technology is a great help, but decent offices are essential.

On a personal note, imagine my excitement at moving into a set of offices that have an immediate impact. In Portcullis House, I feel even more energetic and industrious – and proud to be an MP. So splendid are they that I even come in on Sunday evenings so that I can start each week on top of my work. Many MPs work late at night and one of the many strengths of Portcullis House is that at night it takes on a life of its own.

Looking out of the window of my new office, I can survey London Eye and County Hall, where I worked in the years before Ken Livingstone's regime. My mother was an Inner London Education Authority member and my husband's greatgrandfather was leader and chairman of the London County Council. I can see St Thomas' hospital, where both my son-in-law and my daughter work as doctors and where my father was once chairman of the governors.

The story of Portcullis House is one of struggle, stamina and success against the odds. The architect, Sir Michael Hopkins, has worked on this project for 12 years; a good part of a career. The announcement about the redevelopment of the squalid Victorian buildings on the site across Bridge Street from the Palace of Westminster was first made in the early 1960s. For decades there was delay and indecision, much of it caused by proposals for a new Tube line. Now we have a brand new Underground station, also designed by Sir Michael. It is a splendid achievement. The vastly improved facilities now match the glory of the neo-gothic Palace of Westminster designed by Bar and Pugin.

Great thought has gone into the arrangement of internal spaces. Each MP has an area of 20 m2, which was the basic standard for an assistant secretary in the civil service. However, each room has a bay window that juts out from the main face of the building, which though tiny, gives an enormous feeling of extension. The window holds a leather bench, giving MPs somewhere to sit where they can look up and down the street.

The seven-storey building is arranged as a doughnut of offices enclosing the central courtyard. The outer ring is 13.2 m deep and accommodates two rows of offices with a central corridor. Because it is such a noisy corner of London, the windows are sealed and triple glazed. The offices overlooking the courtyard come with french windows and a tiny balcony so that the door can be opened for fresh air.

There are many innovative features of Portcullis House that are not immediately apparent. For instance, instead of conventional air-conditioning, a state-of-the-art ventilation system circulates fresh air and saves energy.

Fresh air is drawn in through grilles at the base of the prominent rooftop chimneys, circulated, then expelled through the top of the chimneys. Cooling is provided by groundwater drawn up from a borehole drilled 170 m below ground. The result is that the internal environment is noticeably fresher than in the usual modern office.

As it was constructed on top of the complex Underground interchange, the entire office building is supported on just six huge concrete columns that descend to the station. Lifts and staircases are suspended from the roof, that also holds the ventilation and heating plant. The undercroft that makes up the Underground stations is more like Gruyère cheese.

Each room is enclosed within partitions and a vaulted ceiling of precast concrete. The concrete panels act like a night storage heater: absorbing the heat in the day and radiating it out during the night when MPs are working.

Artificial light, that scourge of modern office life, has been reduced to a minimum in the offices. An ingenious light shelf has been introduced with glass prisms that reflect daylight up on to the ceiling. The light shelf also provides shade from glare when the sun is low in the sky, making it possible to read the computer screen at all times.

Reflecting its relationship as an extension of the Palace of Westminster, many of the design features reflect, albeit with a contemporary twist, elements introduced 150 years ago. As in Pugin's palace, the new fittings are made of oak, but in a much less ornate design.

The central courtyard, which is the size of the medieval Westminster Hall, is similarly spanned, without intermediate columns. The magnificent glass roof is supported on a diagonal lattice-work of timber beams connected by modern steel joints. The design is intended to be intricate and give a sense of containment.

Much is made of the unfulfilled potential of select committees that have been stymied by our old-fashioned committee rooms in the Victorian palace. The select committee rooms that make up the first floor of the new building could give a much needed boost to the proposed reforms to the work of the House of Commons.

Portcullis House provides overhead projection arrangements, facilities for laptop computers and sophisticated audio systems.

To my knowledge, there is nowhere else in the House of Commons where it is possible to see film on a screen, instead of just a small television. Also for the first time, there are translation facilities and spaces for stenographers.

Impressive tapestries designed by Kate Blee, Jenny Moncur, Judy Clarke and Alegra Hicks look splendid and make a contribution to sound absorption.

Especially good use has been made of Sir Edward Barry's 1870s subway beneath Bridge Street, constructed to link the Palace of Westminster with St Stephen's Club and the Underground station. A new escalator leads directly from the passage into the courtyard of Portcullis House.

In addition, disabled access has been fully integrated, with offices and committee rooms easily accessible to people in wheelchairs.

The former speaker, Betty Boothroyd, has rebuked MPs for failing to discharge their responsibility to hold the government to account. Without doubt, the improved facilities for MPs and the value placed on their work by this magnificent investment, will reinvigorate democracy at Westminster.