Can I ignore the claim form and particulars of claim?

If you do so, the Claimant would apply to the court for a judgment in default and subsequently apply for execution of the judgment. Your property will be at risk; you or your company may face a bankruptcy / winding-up order. Practically speaking, it will cost more to resist the execution application and apply to set aside the judgment in default. It is, therefore, imperative to seek for legal help from the beginning if you believe the claim is without merits.