130 community groups will attend a summit in Aylesbury later on the government's plans to build a high speed railway line through the Thames Valley.
15 local authorities from across the South have launched a legal challenge to plans to build the £32 million pound line from London to Birmingham.
The government believes that HS2 is necessary to improve the UK's infrastructure and the economic prospects of the North of England.
The Lord Lieutenant of Buckinghamshire will chair the summit which will focus on the environmental impact of the project.
Alison Munro the CEO of HS2 Ltd is expected to attend.
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Wednesday lunchtime's weather for the east of the region
Wednesday lunchtime's weather for the west of the region
There is a high risk from birch pollen during any good weather. Oak pollen is also on the increase.