Proposals for three tall buildings next to Waterloo Station - which critics say will damage the Palace of Westminster and its surroundings - are being scrutinised at a public inquiry which opened this week.
Mayor of London Boris Johnson had initially opposed the towers but then did a last-minute U-turn and decided not to intervene.
Last October, after pressure from English Heritage, communities secretary Hazel Blears ordered a public inquiry into the proposals which could create nearly 4,000 jobs and up to 280 homes.
The secretary of state has asked the inquiry to consider a range of matters including "the appropriateness of tall buildings in this location" and whether the scheme complies with policies designed to protect conservation areas in Lambeth and the Westminster world heritage site from damaging development.
Christopher Katkowski QC, for P&O and Lambeth Council, began his remarks by describing the current buildings as "grotty relics of the 1960s".
"No sensible person would mourn their demolition," he said. "The sooner they are replaced with a good quality contemporary redevelopment, the better, not least so as to bring about much-needed public realm and permeability improvements on this strategically placed site where there is an outstanding opportunity to link and integrate the South Bank and Waterloo Station."
He described the site in York Road as "a truly sustainable location for tall buildings" and went on to highlight the track record of Allies and Morrison: "The scheme architect, Graham Morrison, is a passionate promoter of the renaissance of London south of the river ... So one would have thought that the applicant has chosen the right firm and the right man for this pivotal site."
Mr Katkowski accused English Heritage and Westminster City Council of "sour grapes" for claiming that highly visible tall buildings on this site are not supported by planning policy.
Referring to previous public inquiries into schemes for tall buildings in SE1 – including the Shard of Glass, Doon Street and Blackfriars Road – and elsewhere in the City, Mr Katkowski said: "Successive secretaries of state have seen the bigger picture and disagreed with the objections made by English Heritage and Westminster City Council in these seminal cases.
"The ministerial view over time has acknowledged that being able to see good quality contemporary architecture in the same view as heritage assets is either a good thing and nothing to get agitated about, or at least not such a bad thing that permission should be refused."
He added: "My point is that one has to be cautious about being beguiled into believing that this scheme really would be the most terrible blow to heritage assets in London when this tune has been played so many times before and not found favour with ministerial ears."
Mr Katkowski concluded: "Had we planned this great and dynamic city on the basis of pictures of the settings of now listed buildings as they were 100 or 50 or whenever years ago, we would be living and working in a museum and not one of the very few cities that can rightly be described as a world city."
"English Heritage supports the redevelopment of the application site, and is neither opposed to tall buildings generally in London nor on this site in particular, so long as such buildings do not unacceptably harm heritage assets or their settings," Neil King QC told the inquiry.
"There are cases ... where English Heritage believes that the harm that would be caused to the historic environment is so significant that the refusal of planning permission is likely to be justified regardless of other considerations. This is such a case."
He went on to describe the impact of the proposals on the Westminster World Heritage Site: "The buildings here symbolise parliamentary democracy, not just for the UK but for the whole world," he said.
Mr King told the inquiry: "The development would substantially fill the gap [gap between the (Big Ben) clock tower and Portcullis House] and would, as a result, cause serious harm to the setting of the grade I listed Palace of Westminster."
He added: "The application would also have an unacceptable effect on the setting of County Hall ... The building's symmetry as viewed against the sky (as presently it can be) would be severely disrupted, and the scale of the buildings would dominate County Hall and its setting."
Turning to the view of the Royal Festival Hall from Victoria Embankment, he said: "Again, the scale and height of the new buildings would dominate and appear incongruous with the much lower Royal Festival Hall."
In the case of the National Theatre, he said: "The carefully created tension between the horizontal and vertical elements of the design would be severely compromised by the height and scale of the application proposals..."
In his conclusion Mr King said: "The harm that these proposals would cause to the historic environment in substantial.
He continued: "The site may be a suitable one for the development of tall buildings; but the buildings proposed in this application are too tall.
"A revised scheme in which the heights of the buildings are significantly reduced could remove any impact on the Westminster World Heritage Site."
Peter Harrison QC, for Westminster City Council, began by highlighting the "clear benefits" of the replacement of outdated offices, the provision of new housing and the improved public space.
But, he cautioned, the proposals "will cause harm to heritage assets" by "damaging the setting and appreciation of key listed buildings, by damaging the setting and appreciation of the Parliament Square world heritage site and other key views of London and the river".
Mr Harrison said: "It is as unhelpful and unfair to label all those opposed to these proposals as opponents of progress, regeneration and the 21st century compact city as it is to label those in favour as cultural vandals who have no concern whatsoever for the value of cultural heritage assets to London and the country as a whole."
Turning to the view from Parliament Square towards the river, he said: "There are very few buildings that are well-known throughout the world simply by their silhouette: the Taj Mahal, the Eiffel Tower, Sydney Opera House.
"But one which is iconic and universally recognised is the outline and presence of the Houses of Parliament viewed from Parliament Square."
He added: "The proposals are not truly for tall buildings as considered by the guidance and policy documents. They are for supertall buildings. And for three of them, forming a tight group."
Mr Harrison asked: "What are the planning benefits that these proposals bring which redevelopment up to the 55 metres (that's 12 to 13 office storeys or 14 to 15 residential storeys) which [Robert Ayton, director of planning and city development at Westminster City Council] sets out as acceptable would not? And do those additional benefits outweigh the degree of harm found to be caused to the heritage assets?"
Graham Morrison talked through some of his practice's previous projects, including the masterplan for the 2012 Olympic park in east London, the King's Cross railway lands redevelopment, White City, Liverpool One and the Bankside 123 development in Southwark.
He also highlighted his firm's work on the award-winning refurbishment of the Royal Festival Hall and the changes made to pedestrian routes around that building.
Turning to the Elizabeth House site, he told the inquiry that his scheme "brings activity and vibrancy to the hinterland of the South Bank quarter".
Talking about the wider Waterloo area, he said: "I think this has the potential to be one of London's truly remarkable places".
Waterloo, he said, ought to be in the top 10 great railway stations in the world.
A Bishop's ward councillor has slammed the "ugly" towers in an interview published in the latest issue of Lambeth Council's Lambeth Life newspaper.
"From a personal point of view the new buildings are ugly, don't really consider the people who will have to live next to them and will be seen as one of the council's mistakes," says Cllr Gavin Dodsworth.