140. He further directed himself on the materiality of alternative sites at IR 15.164 whilst expressing caution about the prospect of alternative sites, which, as mentioned, formed the basis of Mr Drabble’s submissions on this ground: “It is reasonable to suggest that if there are alternative locations for a proposal which would avoid an environmental cost, then these should be taken into account when determining the acceptability or otherwise of the proposal at hand. This is a particularly attractive prospect if it is held that there are viable alternatives sites that could accommodate the proposal without attendant harm.” “But such an approach has to be treated with caution. Whilst (as the Courts have determined) the desirability of having alternative proposals before the Inquiry may be “relevant and indeed necessary”, (though not always essential), in order that it may garner significant weight, the merits of such alternatives must, logically, be underpinned by a good measure of evidence demonstrating their viability and credibility as such an alternative. 501 [8.62, 9.65]” 141. Having identified the three primary alternative sites (IR 15.165) he narrowed his focus to the site at the Imperial War Museum stating that it is on this site “that the hopes of those opposing the VTG proposal are focused as a credible alternative worthy of weight in the planning balance… Such an interest is not without justification” (IR 15.166). He went on to address the relative merits and disadvantages of the Imperial War Museum site. As to its merits: the Imperial War Museum site was one of the sites identified in the Holocaust Memorial Commission report; there are obvious synergies with the existing and proposed Holocaust content of the museum; it is an institution familiar with handling large numbers of people; it has a landscape context that could accommodate a combined Memorial and Learning Centre, and there is a provisional scheme by a distinguished architectural practice testing its feasibility, albeit this is limited in scope. Moreover, the Holocaust Memorial Commission saw the advantage of the site, as previously stated, in it being “within easy reach of Westminster”. He then turns to address the disadvantages of the site including his view that ‘there are serious questions’, as to whether it would meet the critical Holocaust Memorial Commission requirement for a prominent and striking memorial (IR15.167). Further; he went on to state that ‘it is at least apparent to me that the IWM site is not free from constraint.’ He listed the constraints as including: a Grade II listed building and works which could affect its special interest; a conservation area; potential impact on two mature trees on the site; loss of public open space and early years play and learning facility; less well developed security infrastructure and implications for local residents. He concluded that “Clearly, achieving a combined facility here would also involve the balancing of benefits against possible harms, some not dissimilar to those at VTG” (15.168). This is the context in which he arrives at the view that “whilst seeming to offer a benign alternative, IWM lacks a detailed scheme that would meet the core requirements of the HMC and carries clear potential constraints that may hamper its delivery. Together this suggests that the weight to be afforded the IWM alternative in the planning balance is very limited.” (IR 15.169). He then turns to consider timing of construction/installation of the Memorial and the importance of delivering the 52