Magento show discount in cart page even without applying a coupon - magento

Question

In cart page we can see the discount row only if a customer add a coupon code(?). What I want to do is adding the discount as zero for every cart page even there is not any coupon code applied.
What I see:
Total (Inc VAT) £42.00
Subtotal (net) £35.00
Subtotal (Inc VAT) £42.00
VAT £7.00
What I want:
Discount £0.00
Total (Inc VAT) £42.00
Subtotal (net) £35.00
Subtotal (Inc VAT) £42.00
VAT £7.00
This is my design/.../template/checkout/total/default.phtml file for viewing discount with coupon code:
<tr>
<td colspan="<?php echo $this->getColspan(); ?>" style="<?php echo $this->getTotal()->getStyle() ?>" class="a-right">
<?php if ($this->getRenderingArea() == $this->getTotal()->getArea()): ?><strong><?php endif; ?>
<?php echo $this->escapeHtml($this->getTotal()->getTitle()); ?>
<?php if ($this->getRenderingArea() == $this->getTotal()->getArea()): ?></strong><?php endif; ?>
</td>
<td style="<?php echo $this->getTotal()->getStyle() ?>" class="a-right">
<?php if ($this->getRenderingArea() == $this->getTotal()->getArea()): ?><strong><?php endif; ?>
<?php echo $this->helper('checkout')->formatPrice($this->getTotal()->getValue()) ?>
<?php if ($this->getRenderingArea() == $this->getTotal()->getArea()): ?></strong><?php endif; ?>
</td>
The problem I'm having is whenever cart page is loaded, this block won't load, unless there is coupon code applied, obviously. What I want to know is that is there any flag or controller for make the block appear even no coupon is applied so in above block I can check whether coupon is applied or not to customize the above view. Can you give me any suggestions?
PS: here coupons means shopping cart price rules.