The family of a teenager who suffered a fatal allergic reaction at a burger restaurant say they have not ruled out legal action.
Owen Carey told staff at Byron at the O2 Arena in London about his dairy allergy but was not told his grilled chicken meal included buttermilk.
His inquest heard he had been misled into thinking it was safe for him.
Paul Carey said Byron had treated the family "dishonourably" in the wake of his son's death.
"Most companies should have a sense of corporate responsibility and I think Byron have forgotten that," he told the Victoria Derbyshire programme.
"It was clear from the way they behaved within the inquest, and their barrister and their witness, they were just looking to protect themselves."
Asked if he had considered legal action against the chain, Mr Carey replied: "Well it's not ruled out, put it that way."
Owen, who was celebrating his 18th birthday at the restaurant, experienced tingling lips and stomach problems after eating half of his chicken, the hearing was told.
The teenager collapsed 55 minutes later outside the London Eye.
His family is campaigning for "Owen's Law" which would call for better allergen labelling in restaurants.
'Distinct lack of empathy'
Emma Kocher, Owen's sister, said: "Byron have really upped their game and they do go above and beyond now what is the current legislation and they do proactively ask if anyone does have any allergies."
But she said Byron should start doing what was being proposed in Owen's Law and list all components of their dishes.
"There's still a lot more work to do," she said.
Regarding the firm's conduct towards them, she added: "We believe there's been a letter sent, but we haven't seen it yet, so we don't know if they have apologised.
"There's been a distinct lack of empathy."
Byron has been approached for a comment, but earlier posted on their website: "We will be writing to the Carey family to see if we can get involved in their courageous efforts to introduce an Owen's Law and improve allergy awareness and standards in restaurants."
The family told the BBC they take a photo of Owen to all their interviews.
"We want everyone to know who he was. He was a real person. He's still a member of our family," his father said.
What is the law on food allergy labels?
There are 14 allergens that food providers must alert people to, including nuts, milk and eggs.
Pre-packed food must have an ingredients list and, under "Natasha's Law" which is due to come into effect on 1 October 2020, allergens must be emphasised in some way every time they appear.
For non pre-packed food, such as that sold in a restaurant, information for every item that contains any of the 14 allergens must be provided.
According to the Food Standards Agency, this could be either on a menu, chalkboard or information pack, or through a written notice explaining how customers can find out more information, for example by asking a member of staff for details.
But Mr Carey's family said this "leaves far too much room for error".
They want it written beside each item on the menu which contains an allergen.