All-Party Parliamentary Gardening & Horticulture Group organiser Mark Glover said: "We are delighted to welcome a figure of Alan's stature in the 10th year of the group. This celebrates the strides the horticulture industry has made over the past 10 years and improved its relationship with Parliament."
Defra secretary of state Hilary Benn will give the keynote address at the event, which will be held at the Houses of Parliament.
Garden retailers, landscapers, growers and green space professionals will lobby MPs and Lords at the event.
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