A new law to bolster workers' rights by making it an employer's job to prevent staff being harassed by customers and clients, as well as fellow colleagues, has been criticised by some as an attack on free speech. Opponents worry that harmless banter - in pubs, for example - might need to be monitored as a result of this new legislation. That's denied by the government. The word ‘banter’ has seen a resurgence in the last few decades. Tony Thorne, a lexicologist and language consultant at King’s College London, tells Adam when the banter began.