Fortress around your heart

Under the ruins of a walled city
Crumbling towers and beams of yellow light
No flags of truce, no cries of pity
The siege guns had been pounding through the night
It took a day to build the city
We walked through its streets in the afternoon
As I returned across the fields I'd known
I recognised the walls that I once made
I had to stop in my tracks for fear
Of walking on the mines I'd laid

And if I built this fortress around your heart
Encircled you in trenches and barbed wire
Then let me build a bridge
For I cannot fill the chasm
And let me set the battlements on fire

Then I went off to fight some battle
That I'd invented inside my head
Away so long for years and years
You probably thought or even wished that I was dead
While the armies are all sleeping
Beneath the tattered flag we'd made
I had to stop in my tracks for fear
Of walking on the mines I'd laid

And if I built this fortress around your heart
Encircled you in trenches and barbed wire
Then let me build a bridge
For I cannot fill the chasm
And let me set the battlements on fire

This prison has now become your home
A sentence you seem prepared to pay
It took a day to build the city
We walked through its streets in the afternoon
As I returned across the lands I'd known
I recognised the fields where I'd once played
I had to stop in my tracks for fear
Of walking on the mines I'd laid

And if I built this fortress around your heart
Encircled you in trenches and barbed wire
Then let me build a bridge
For I cannot fill the chasm
And let me set the battlements on fire