But commentators see reasons to be optimistic that planning policy could escape relatively unaffected. Certainly, the appointment of Barwell to be Prime Minister Theresa May's Downing Street chief of staff suggests any major deviations from the thrust of the white paper are unlikely. The practical logic of minority government - that politicians are only able to pursue policies with a wide degree of consensus - also appears to limit the threat to the government's broad housing and planning agenda. Both main parties are signed up to build 200,000 homes a year. Barwell had already knocked many controversial elements out of the policy platform he inherited from the David Cameron era, such as stipulations about the proportion of housing schemes that should be made up of discounted Starter Homes and cuts to funding for affordable rented housing.

Martin Curtis, associate director at public affairs company Curtin & Co, said: "The Conservatives will want to take forward the housebuilding agenda in the manifesto. I don't think that's particularly controversial across parties and I think they'll be able to deliver it." In fact, the outcome of the election could even strengthen government resolve. Matthew Spry, senior director at consultants Lichfields, said: "The political message from the election - the power of the young vote - reinforces the need for policy objectives on housing."

However, while the overall agenda may not be in doubt while May remains in charge, for individual white paper measures or manifesto pledges to survive may depend upon cross-party support. Hence the Conservative manifesto pledge to capture land value created in the planning process could be explored with Labour support, despite being controversial with developers. Duncan Field, UK head of planning at law firm Norton Rose Fulbright, said: "Some of the more controversial changes which both of the main parties hinted at around the capturing of land value uplift are now much more likely to be implemented."

In fact, many suggest the bigger threat to the agenda will stem from backbench Tories in rural seats rather than the Labour opposition. Experts say policies likely to be controversial with the anti-development wing of the party include the manifesto pledge to introduce a permitted development right for exploratory fracking. Roger Hepher, founding partner of consultants Hepher Grincell, said: "I suspect now this idea will be quietly dropped."

Other vulnerable measures include white paper proposals to establish tests which could determine whether green belt site allocations could be considered and a new housing delivery test for councils. Spry said: "There has to be a potential concern that the nuanced approach to green belt set out in the white paper could become lost." Hepher warned: "There could be a rowing back on enforcing housing delivery, given the concerns of the Tory backwoodsmen. Inevitably they're going to be listened to very hard."

The government could even seek to work with the opposition to enable it to face down opponents within its own party. Curtis said: "If they're smart, the government could do with compromising a bit with the Labour agenda, but I suspect that will prove too politically challenging."

The biggest fear of many, however, is that the hiatus from the election and appointment of a new minister will herald delays which will, of course, be drastically worsened if Theresa May's administration collapses. Simon Ricketts, partner at law firm Town Legal, said Barwell's successor would likely look again at the white paper. "The incoming minister is going to have to review it and produce a refreshed version," he said.

Any delay could impact upon local plan formation. Mark Sitch, senior partner at consultants Barton Willmore, said: "If the government doesn't progress its plan, such as amendments to the National Planning Policy Framework, it could mean local plans will be pushed back again, with the government not in a position to intervene."

Key planning pledges: will they now be pursued?

The Conservative Party's election manifesto made a series of planning promises. But how likely are they to be implemented following last week's surprise general election result, which leaves the party without a parliamentary majority?

1. Reforms to capture land value uplift from development and to the compulsory purchase order (CPO) process to make it easier for councils to use. Simon Ricketts, a partner at law firm Town Legal, said these elements of the manifesto would be "threatened" by the fact that "anything politically difficult or complex" will now find it difficult to gain traction. Ian Anderson, executive director at consultancy Iceni Projects, said: "The big challenge is whether there's enough parliamentary air time to deal with what could be a pretty heavyweight piece of legislation."

Matt Thomson, head of planning at the Campaign to Protect Rural England (CPRE), said: "The CPO reforms are largely already in the Neighbourhood Planning Act, which just needs a commencement order and some regulations to get going.

Land value uplift is gathering cross-party and cross-sectoral support as a means of accelerating housing delivery, so it could be an easy option for a government keen to be seen to be doing something positive."

2. Support for high-quality, high-density housing "like mansion blocks, mews houses and terraced streets". Kathryn Hampton, a senior professional support lawyer at Hogan Lovells, said this policy is likely to be brought forward, given cross-party support to boost housing delivery. She said: "I can see this being a more popular option because of controversy over the alternative of green belt development." Dominick Veasey, an associate director at Nexus Planning, agreed that higher density is something the government "would be keen to proceed with", given the level of cross-party support for "making better use of urban and brownfield sites".

3. Allowing shale gas production applications to be pursued via the fast-track development consent order process for major infrastructure schemes. Commentators agreed that this policy is likely to be dropped as it would be too controversial among many voters and other parties, including Labour, are opposed to it. Hampton said support for fracking would probably be "bottom of the list" of priorities for the new minority government. Anderson said: "I think this is dead. It's both logistically and politically difficult. Quite a lot of shale gas applications are in Tory areas." Veasey predicted that, without a strong majority, the Tory government would face "strong parliamentary resistance" to any legislation enacting the measure. He added: "I suspect they may row back on this completely."

4. Delivering the planning reforms proposed in February's Housing White Paper, including changes to the National Planning Policy Framework (NPPF). Many commentators said the loss of planning minister Gavin Barwell would delay the measures' progress, given his close association with the white paper. Anderson said: "We are almost certain to see delays in the consultation around changes to objectively-assessed housing need and the NPPF review. I imagine that will get pushed back until next year."

But Cian Bryan, a director at think-tank Planning Futures, said that, given Barwell's new influential role as the Prime Minister's chief of staff, "I fully expect to see the policies outlined in the Housing White Paper to be brought forward over the coming months."

Thomson said a lot of the paper's proposals are already in the Neighbourhood Planning Act and just require a commencement order or regulations to be issued, "which could be achieved pretty quickly". He added: "We do not expect much to change with the Housing White Paper."

5. Delivering a million new homes by the end of 2020 and half a million more by the end of 2022. Commentators agreed that this was an uncontroversial proposal that had cross-party backing, though they questioned whether the target is achievable. Bryan said: "Given the apparent rise in the young vote at this election, I think ministers will be particularly keen to address issues surrounding the housing crisis and may push policy forward with renewed vigour."

Source: Planning Resource