create opening in support wall 2.7 metre wide as wide as possible support with beam or lintel to building regulation

This sort of alteration falls under building control for two reasons the first Part A of the regs deals with structure. This is why the loadings need to be calculated by a structural engineer. Then the work needs to be inspected to ensure that the live loadings are suitably transmitted to the foundations and placed on 7 kilonewton concrete pad stones with the correct size beams to avoid deflection. Then Part B of the regs which requires that the beams are suitably fire protected to avoid deflection and warping in a fire for 1/2 hour. This is to allow safe escape from the property in the event of fire and is not designed to save the building. Fire protection can be either intumissant paints or fireline boards which are cheaper in commercial building encapsulation in concrete is also used. Solid timber can also be used as this chars in fires and does nor buckle like steel will however this method would be used in historical scenarios. The general rule of thumb for domestic scenarios is 200mmx 100mm beams bolted together for 2 storey dwellings. Hope this answers your question Paul BBC

You will need a calculated steel beam to take the load,this would have to be checked and signed off by a building inspector.

Yes. Any structural openings or alterations come under building regulations.

You will need building regs and universal steel beam but the size is dependent on the loads it will carry above.