Barriers make a good place to rest weary legs

While many acknowledged the good intentions behind the grey, inanimate barrier, others were less than charitable, describing it as "unsophisticated" and saying it "defaced" a beautiful landmark.

Jose Antonio, 36, an architect on a flying visit from New York, said: "It's ugly but I think it is necessary. It doesn't make me feel any safer.

"Maybe the people inside feel safer and the building is better protected though."

At Grand Central Station in New York there is more of a police presence than actual physical barriers Elisa Columna

His friend Elisa Columna, 31, an urban planner, said: "I think they could do something better.

"There are so many things technology can bring - than concrete blocks. It is not very sophisticated. I think more security would be better.

"At Grand Central Station in New York there is more of a police presence than actual physical barriers."

Retired Ministry of Defence worker Patrick Hudson shook his head as he looked at the concrete construction.

"I honestly cannot see what they are trying to do - what are they going to achieve?

"A car wouldn't get in, but a bomber would," said Mr Hudson, on a day trip from Portsmouth.

Liz Gelder: 'This is better than nothing'

His wife Marlene added: "It's not going to save the buildings."

Liz Gelder, a hospital receptionist on a visit to the capital from Hull, Yorkshire, said: "Unfortunately it is a sign of the times.

"I suppose it makes me feel safer because I feel that there are things going on in the background that none of us know about that will hopefully produce the measures to cut the risk of terrorism.

"I can't see that it will stop terrorism, but this is better than nothing."

'Safe MPs'

Danielle Soubeste, an English teacher with 47 students on a trip from Tartas in the south west of France, said while she understood why the blocks were there, they "defaced" the Houses of Parliament.

"I think it is a good idea except that it is not attractive, but you have got to protect yourselves."

Marlene Hudson: 'It's not going to save the buildings'

Mme Soubeste said she felt safe in London generally. "I don't feel I am a target at the moment but possibly the barriers will make the people sitting inside Parliament feel safer."

One London-based worker, who did not want to be named, said the barricade might stop a vehicle trying to get through, "but not anybody walking through or trying to jump over it".

"I think we have to put up with it, but it is a shame it looks so ugly."