London Has Fallen: New film tells story of terrorists descending on the capital

It's a chilly March morning and I am running through in my head what I'm going to say for the piece to camera I'm about to film outside St Paul's Cathedral.

This is a normal part of my job, but on this occasion, fact has been replaced with fiction, and I'm not in London, I'm on a film set in Bulgaria.

The makers of new film "London Has Fallen" had ambitions for an element of realism so cast real-life news reporters and presenters - hence I got the call to take a turn as myself.

As the explosive trailer shows, the capital gets an absolute pounding in this sequel to the 2013 hit "Olympus Has Fallen".

Many a famous landmark is destroyed as the film tells the story of terrorists descending on London to try and assassinate world leaders who are in the city to attend the funeral of the British Prime Minister, who has died in rather mysterious circumstances.

The idea of a fictional terrorist attack in London has been greeted with some mutterings of discontent.

The trailer was released in the same week last July as the tenth anniversary of the 7/7 bombings, with some branding it insensitive.

It's notable there's no extravagant London premiere for the film - the big event took place on Tuesday night in Los Angeles, complete with fake soldiers from the Queen's Guard.

It could just be a logistical issue getting the talent to the UK, or maybe producers decided it wasn't worth any potential bother. Either way, it will be in cinemas here from today.

As my experience with this film is proving, it is much more Hollywood than London.

The capital always looks good in the movies and this is very much an American take on events, with the story focusing on saving the President of the United States from a very public execution.

The other leaders, even those that get killed off, are asides to the main action.

And this is one action packed film... which takes me back to Bulgaria. Why on earth would I be flown out to Sofia for a couple of days when I could just wander up the road from the day job in London to St Paul's and shoot my scene there?

The perhaps obvious reason is, you can't exactly have major gunfights and explosions happening around London's most iconic landmarks (although some filming did take place in the capital).

The set of the fake St Paul's Cathedral in Bulgaria is impressive. There is no famous dome - that will be added using visual effects later - but the fake steps, the fake Queen Victoria statue and the fake signage are spot on.

There are people everywhere. Some are extras dressed as British bobbies or security guards and others are running around with gaffa tape and clipboards. There is also a lot of hanging around, which for a nosey journalist like me, means I start to ask questions.

It was requested that anyone on set didn't take photographs or post confidential information about the film on social media. However, when director Babak Najafi came over for a chat I turned true cheeky journo and asked if he minded if I took a photo.

He very pleasantly replied "not at all" and we were joined by a couple of other actors (Brit Guy Williams and LA based actor and stuntman Joe Fidler). I think I've done well to wait a year to share it!

After a little while I got to do my bit, talking about the "security at unprecedented levels ahead of the funeral" and how "it's the most protected event on Earth". If I was doing the day job, I would usually be just doing this with one camera person - here, I was doing it in front of dozens of crew and watchful eyes.

It was all over very quickly but Babak said I was welcome to stay on set and watch as more filming took place with the headline stars Gerrard Butler, Aaron Eckhart and Angela Bassett.

It was fascinating for an outsider like me and as I perched on a cast chair in the chilly Bulgarian breeze, my assigned assistant for the morning brought me a hot water bottle. (I hope my ITV News bosses are taking note...)

During that time I found out more about how life was as an actor in LA from Joe Fidler, how every piece of armoury on set was heavily scrutinised by leading experts and how security specialist Will Geddes had advised the film-makers on making the work of the fictional secret services look as authentic as possible. It was also very clear that making movies is a slow process (especially compared with news programmes) and by the time the water in my hot water bottle had cooled, I decided to head back to my dressing room.

The couple of hours of work I'd witnessed would probably equate to no more than 30 seconds of the actual film.

Fast forward almost a year to today and the movie is finally hitting the big screen. In recent weeks I have had a sneaky feeling my short scene wouldn't make the final cut so my new LA friend Joe said he'd let me know after attending the premiere.

The bad news came through the following morning - not only was I cut, so was he! Harsh. That's Hollywood for you.

Thank goodness I took those photos... so now back to the day job.