"(snip....) Lintel construction has changed with various methods and materials now in use such as flat soldier course lintels, pre stressed concrete lintels and catnic lintels. They can all fail for various reasons such as changes in structural loads, ground movement, and thermal expansion, and in concrete lintels fail due to oxidisation of the reinforcing bar.(snip...)" (Brit site, Brit spelling....)
That looks decorative. I bet there is a real steel lintel behind that over the window giving support.