This is the mysterious web left on a hedge at the Bradford offices of Yorkshire Water.

However, after running an online campaign, the firm discovered the culprits were not spiders but Cotoneaster webber caterpillars, commonly known as Hawthorn webber moth.

The small brown caterpillars feed beneath silk webbing which happens every year between April and June and late July and August, with the Western House, Halifax Road office targeted.

A Yorkshire Water spokesman said: “A mysterious spider like web appears on a hedge outside of our main offices in Bradford every year.

“The plant is eye catching and we decided to run a competition last month asking our followers on Twitter if they knew what it was.”