In The Garden: tall, spindly, blue flowering plant

I am assuming this plant has sown itself from birdseed? We've only been in this house just over a year and all last summer we just mowed over what looked a bit like a lettuce that kept growing back. This year, we decided to let it grow and this is what happened...any ideas anyone please?

 

Chicory

 

Cichorium endivia ?

 

Thanks for your prompt reply, definetely came from the bird seed!