What it's like to tackle the UK's highest roof walk

As someone who doesn't mind heights, but has a slight fear of rope-based climbing, I did briefly wonder what on earth I'd signed myself up for after agreeing to take on the UK's highest rooftop climb.On Valentine's Day, London's iconic Alexandra Palace will launch Summit: Ally Pally Rooftop Adventure, officially the UK's highest roof walk, standing 130 metres above sea level.