*@greasyshoes
*
Here, indecent means "not conforming with generally accepted standards of behaviour, especially in relation to sexual matters." In other words, illegal material.
And? You believe viewing pornography in a public place is a generally accepted standard of behaviour? Really?
I think you'll find it's not and you're in a minority.
Children (many primary aged) on school trips are regularly in the gallery of the chamber of House of Commons observing debates and learning about British democracy.
Are you saying you think it's ok for children to be exposed to pornography via 3rd party?
The MP's phone would be visible from above, as has been confirmed by Jo Coburn BBC politics show presenter; he wasn't being discreet as two female MP's witnessed it and reported him.
It's akin to indirect sexual harassment, and that MP is a deviant.